North Warwickshire Borough Council, R (on the application of) v The Secretary of State for Transport & Anor [2026] EWCA Civ 832

[2026] EWCA Civ 832Case No CA-2025-001450
IN THE COURT OF APPEAL (CIVIL DIVISION)
[2025] EWHC 1248 (Admin)
ON APPEAL FROM THE HIGH COURT OF JUSTICE
KING’S BENCH DIVISION
PLANNING COURT
MR JUSTICE DOVE
Venue Royal Courts of Justice, Strand, London, WC2A 2LLDate 30/06/2026
Before
LORD JUSTICE BEAN(Vice-President of the Court of Appeal (Civil Division))LADY JUSTICE KINGLORD JUSTICE HOLGATE
Between
NORTH WARWICKSHIRE BOROUGH COUNCILAppellant(1) THE SECRETARY OF STATE FOR TRANSPORTRespondents(2) THE SECRETARY OF STATE FOR HOUSING, COMMUNITIES AND LOCAL GOVERNMENTInterested PartyHIGH SPEED TWO (HS2) LIMITEDInterested Party
Craig Howell Williams KC and Kate Olley (instructed by North Warwickshire Borough Council) for AppellantJames Strachan KC and Victoria Hutton (instructed by Government Legal Department) for RespondentsTimothy Corner KC and Jacqueline Lean (instructed by Eversheds Sutherland (International) Limited) for Interested PartyHearing Hearing dates : 6-7 May 2026
Approved JudgmentThis judgment was handed down remotely at 11.00am on 30 June 2026 by circulation to the parties or their representatives by e-mail and by release to the National Archives..............................
[1]The High Speed Rail (London-West Midlands) Act 2017 (“the 2017 Act”) authorised “the nominated undertaker”, the interested party High Speed 2 (HS2) Limited (“HS2L”), to construct and maintain a railway between Euston station, London and the West Coast Main Line at Handsacre in Staffordshire, with a spur from Water Orton in Warwickshire to Curzon Street Station, Birmingham, referred to as “Phase One of High Speed 2”. The 2017 Act resulted from a hybrid Bill which was deposited in Parliament on 25 November 2013, along with an Environmental Statement (“ES”) which formed part of the process of Environmental Impact Assessment (“EIA”) for the project.[2]Part of the spur runs through the area of the claimant, North Warwickshire Borough Council (“NWBC”), a local planning authority (“LPA”). NWBC had petitioned against the Bill.[3]Following the passing of the 2017 Act more detailed design work has been carried out on Phase One and some alterations made to the scheme. HS2L decided that a section of the spur about 2.9km long should run in tunnel rather than on the embankments and viaduct authorised by the Act.[4]This appeal is concerned with two issues of statutory construction :(1) Were the revised works authorised by the 2017 Act?(2) If they were so authorised, did those works have the benefit of the deemed planning permission granted by s.20(1) of the 2017 Act?[5]If the answer to either question is no, then it is common ground that the revised works required a separate grant of planning permission under the Town and Country Planning Act 1990 (“the TCPA 1990”). In addition, NWBC maintain that no such permission could be granted without complying with the requirements of environmental impact assessment (“EIA”) laid down in The Town and Country Planning (Environmental Impact Assessment) Regulations 2017 (SI 2017 No. 571) (“the 2017 EIA Regulations”).[6]The respondents, the Secretary of State for Transport (“SST”) and the Secretary of State for Housing, Communities and Local Government (“SSHCLG”) determined HS2L’s appeal against a deemed refusal of its application for a detailed planning approval under the 2017 Act by NWBC. In that appeal HS2L maintained that the answer to the two issues was yes, whereas NWBC said that the answer was no. In their decision letter dated 14 May 2024 the respondents decided that HS2L was correct.[7]In a claim for judicial review NWBC submitted that the respondents’ decision was wrong in law. On 20 May 2025 Dove J (as he then was) dismissed the claim, holding that the respondents had been correct on both issues of statutory interpretation.[8]For the reasons I give below, I respectfully agree with the judge on issue(1) but disagree with him on issue (2). In my judgment: (1) The revised works are authorised by the 2017 Act;(2) But those works do not have the benefit of the deemed planning permission granted by the 2017 Act.

Background

[9]Section 1 of the 2017 Act authorises the construction of works specified in sched.1 to the Act (the “scheduled works”). This case is concerned with three scheduled works along the route of the spur which, running from west to east are works 3/203, 3/200 and 3/157:
“Work No 3/203 – a railway (2.86 kilometres in length, in tunnel) commencing by a junction with Work No 3/200 at its termination, passing westwards and terminating by a junction with Work No 3/205 at a point 245 metres north-west of the junction of Wolsey Drive and Bromford Lane.” “Work No 3/200 – a railway (2.06 kilometres in length) commencing by a junction with Work No 3/157 at its termination, passing generally westwards and terminating at a point 165 metres south of the junction of Cadbury Drive and Beale Close” “Work No 3/157 – a railway (1.13 kilometres in length) partly on viaduct commencing by a junction with the termination of works Nos 3/151, 3/152, 3/153 and 3/154 passing westwards and terminating by a junction with work No 3/200 at a point 317 metres north-west of the bridge carrying the Water Orton Road over the M6 motorway.”
[10]Starting at the western end of these works, 3/203 authorised the construction of a twin-bore tunnel nearby 2.9km in length known as the Bromford Tunnel (“BT”). The western portal was to be at Washwood Heath and the eastern portal at Castle Bromwich. Both of these portals were located in the area of Birmingham City Council.[11]From the Castle Bromwich portal the railway was to continue eastwards on an embankment, then cross the River Tame on a viaduct and then run on a second embankment before descending in a cutting to Water Orton.[12]During the Parliamentary proceedings on the Bill it was acknowledged that the design of the railway might vary from the proposals presented to Parliament as more detailed design work was carried out and also in response to conditions encountered on site. The 2017 Act allows for such variations up to a point, beyond which any necessary authorisations must be obtained and the related procedures followed.[13]During 2020, HS2L decided that the BT should be extended to the east by a further 2.9km, the Bromford Tunnel Extension (“BTE”), so that the tunnel would have an overall length of 5.8km, double the length of the BT. The tunnel’s eastern portal (“BTEP”) would be constructed further to the east so as to emerge in a shortened cutting at Water Orton. The BTE was not a scheduled work authorised by s.1 of the 2017 Act. Although the revised works would lie on the same route as the 2017 Act had authorised, they were not specified in works 3/157 and 3/200.[14]HS2L maintains that the revised works were authorised by virtue of s.2 of the 2017 Act, which empowers the undertaker to carry out a range of “non-scheduled works” described in generic terms and without reference to particular locations. It also contends that the revised works have the benefit of the deemed planning permission conferred by s.20 of the 2017 Act.[15]If HS2L are correct on both of those points, s.20(3) and sched.17 to the 2017 Act impose conditions on that planning permission in relation to those works. In particular, in so far as the revised development comprises “building works” or “other construction works”, paras.2 and 3 of sched.17 require those works to be carried out in accordance with plans and specifications approved by the relevant planning authority, which was NWBC. However, sched.17 imposes restrictions on the extent of the planning controls which a LPA may exercise. Moreover, para.22 of sched.17 gives HS2L a right of appeal against a LPA’s decision on a request for approval, or a failure by a LPA to determine such a request within 8 weeks (which is deemed to be a refusal of an approval). The appeal is to the “appropriate ministers”, the SST and the SSHCLG.[16]On 22 September 2021 HS2L made an application to NWBC for approval under sched.17 of a number of works which included the eastern portal for the BTE at the Water Orton cutting. Apart from the portal, HS2L did not seek sched.17 approval for the rest of the BTE because a tunnel is excluded from the definition of “building works” (see para.30 of sched.17) and because it is considered that a tunnel falls outside the meaning of “other construction works”. NWBC has not contended otherwise and the issue is not before us for determination.[17]On 20 January 2022 HS2L made an application to the SST under the Transport and Works Act 1992 for a Transport and Works Act Order (“TWAO”) amending the description of the scheduled work 3/157 in the 2017 Act by removing the words “partly on viaduct”. Those words relate to a 30m length of viaduct which lies within work 3/157. The amendment would remove any conflict between the specification in 3/157 of a viaduct and the construction under s.2 of the 2017 Act of the BTE. By contrast, the written description of 3/200 did not specify the type of engineering works involved.[18]On 8 October 2021 NWBC declined to determine the sched.17 application on the grounds that the BTE fell outside the 2017 Act. HS2L appealed to the Secretaries of State against a deemed refusal of its application.[19]A hearing took place before an Inspector on 27 April 2022. NWBC contended firstly, that the BTE and BTEP were not authorised as non-scheduled works by s.2 of the 2017 Act; and secondly those works did not benefit from the deemed planning permission under s.20 of the 2017 Act because they would be likely to have significant environmental effects and were not covered by an environmental assessment in connection with the Bill. HS2L disputed both points. In his report to the Secretaries of State dated 31 March 2023 the Inspector agreed with NWBC on both issues and recommended that the appeal be dismissed in so far as it related to the BTEP.[20]The Secretaries of State issued their decision letter on 14 May 2024. They disagreed with the Inspector, allowed HS2L’s appeal in full and granted the whole of the sched.17 approval sought.[21]In its claim for judicial review NWBC sought to challenge the decision of the Secretaries of State in so far as it(1) decided that the BTE and BTE eastern portal benefited from the deemed planning permission and(2) granted an approval for that portal. The substantive hearing of the claim took place before Dove J (as he then was). He rejected all three of the grounds of challenge and dismissed the claim.[22]By the time NWBC applied to this court for permission to appeal, the BTE had largely been completed without any enforcement action having been taken by NWBC. Nevertheless, the parties agreed that permission to appeal should not be refused on the basis that the proposed appeal was academic. The grounds of appeal essentially raise points of construction of the 2017 Act which go to the scope of(1) HS2L’s powers to construct parts of the railway to designs which differ from those considered by Parliament during proceedings on the Bill and(2) the deemed planning permission under s.20. The court was told that the court’s determination of these points of construction will be relevant to the future treatment of revised designs for other parts of Phase One of HS2. However, NWBC no longer seek a quashing order of the decision and now only seek declaratory relief.

The grounds of appeal

[23]There are two grounds of appeal: Ground 1 The judge misconstrued s.2 of the 2017 Act. It does not authorise the construction and maintenance of the BTE. Ground 2 The judge misconstrued s.20(2)(c) of the 2017 Act so as to treat the proposed works as being “covered by an environmental assessment in connection with” the Bill where those works would have no new or different likely significant effects to those reported in the ES for the Bill. He therefore erred in holding that s.20(2)(c) did not apply to those works and that they had the benefit of the deemed planning permission in s.20(1) of the Act.[24]If NWBC succeeds on ground 1, it also follows that the deemed planning permission in s.20(1) does not apply to the BTE irrespective of ground 2. However, if NWBC fails on ground 1, success on ground 2 would provide a freestanding basis for concluding that the deemed planning permission in s.20(1) does not apply to the BTE.[25]In this appeal NWBC did not pursue its third ground of challenge in the High Court which alleged a failure by the Secretaries of State to give adequate reasons for their decision and made a generalised allegation of irrationality. The statutory framework The 2017 Act

The statutory framework

[26]Section 1 of the 2017 Act provides: “1. Power to construct and maintain works for Phase One of High Speed 2(1) The nominated undertaker may construct and maintain the works specified in Schedule 1, being— (a) works for the construction of Phase One of High Speed 2, and (b) works consequent on, or incidental to, such works.(2) In this Act, the works specified in Schedule 1 are called the “scheduled works”.(3) In this Act “Phase One of High Speed 2” means a railway between Euston in London and a junction with the West Coast Main Line at Handsacre in Staffordshire, with a spur from Water Orton in Warwickshire to Curzon Street in Birmingham.” (a) works for the construction of Phase One of High Speed 2, and (b) works consequent on, or incidental to, such works.[27]Paragraph 1 of sched.1 imposes restrictions on the construction of scheduled works in accordance with the plans and sections (defined in s.61) deposited in Parliament for the Bill:
“Construction requirements (1) The scheduled works must be constructed— (a) in the lines or situations shown on the deposited plans, (b) in accordance with the levels shown on the deposited sections, and (c) in the case of any station, depot or shaft for which an upper limit is shown on the deposited sections, within the limit so shown. This is subject to sub-paragraph (2). (2) In constructing or maintaining any of the scheduled works, the nominated undertaker may deviate— (a) laterally to any extent from the lines or situations shown on the deposited plans, within the limits of deviation so shown, (b) vertically downwards to any extent from the level shown for that work on the deposited sections, and (c) vertically upwards to any extent not exceeding 3 metres from the level shown for that work on the deposited sections, but doing so in a case mentioned in sub-paragraph (1)(c) does not increase the limit referred to in that sub paragraph.”
Thus, para.1(2) of sched.1 defines limits of deviation, that is to say limits within which HS2L may depart from the parameters set in para.1(1) by reference to the deposited plans and sections. (a) in the lines or situations shown on the deposited plans, (b) in accordance with the levels shown on the deposited sections, and (c) in the case of any station, depot or shaft for which an upper limit is shown on the deposited sections, within the limit so shown. This is subject to sub-paragraph (2). (a) laterally to any extent from the lines or situations shown on the deposited plans, within the limits of deviation so shown, (b) vertically downwards to any extent from the level shown for that work on the deposited sections, and (c) vertically upwards to any extent not exceeding 3 metres from the level shown for that work on the deposited sections, but doing so in a case mentioned in sub-paragraph (1)(c) does not increase the limit referred to in that sub paragraph.”[28]The relevant deposited drawings show the centre line of each work, its lateral extent and the levels at which it is to be constructed, along with horizontal and vertical limits of deviation from those parameters. The drawings do not show the design of the structures to be built, not even in outline. Instead, they define the limits of the power to construct the works described in sched.1 to the 2017 Act. It was agreed that although para.1(2) authorises vertical deviations downwards “to any extent”, that would not enable a tunnel to be constructed in the place of a work specified to be a viaduct, hence the need for the proposed TWAO. However, it is agreed that the BTE lies within the route authorised by the 2017 Act.[29]Section 2 authorises HS2L to carry out certain non-scheduled works: “2. Further provision about works(1) The nominated undertaker may, for the purposes of or in connection with the scheduled works or otherwise for Phase One purposes, do any of the following within the Act limits— (a) carry out and maintain railway electrification and signalling works; (b) make, provide and maintain all such approaches, bridges, subways, interchanges, roundabouts, turning places, lifts, stairs, escalators, ramps, passages, means of access, shafts, buildings, apparatus, plant and machinery as may be necessary or expedient; (c) construct, provide and maintain all such embankments, aprons, abutments, retaining walls, wing walls, culverts and other works as may be necessary or expedient; (d) demolish the whole or part of any building or structure; (e) alter or remove any structure erected upon any highway or adjoining land; (f) alter, or alter the position of, railway track and any apparatus associated with railway track; (g) alter, or alter the position of, other apparatus, including mains, sewers, drains and cables; (h) alter the course of, or otherwise interfere with, non-navigable rivers, streams or watercourses; (i) carry out and maintain such other works, of whatever description, as may be necessary or expedient.(2) Subsection (1) does not authorise the making of any cut for drainage purposes which is more than 3.4 metres wide at the bottom.(3) The nominated undertaker may within the Act limits— (a) carry out and maintain landscaping and other works to mitigate any adverse effects of the construction, maintenance or operation of any of the works authorised by this Act, and (b) carry out and maintain works for the benefit or protection of land affected by any of the works authorised by this Act.(4) …(5) …” (a) carry out and maintain railway electrification and signalling works; (b) make, provide and maintain all such approaches, bridges, subways, interchanges, roundabouts, turning places, lifts, stairs, escalators, ramps, passages, means of access, shafts, buildings, apparatus, plant and machinery as may be necessary or expedient; (c) construct, provide and maintain all such embankments, aprons, abutments, retaining walls, wing walls, culverts and other works as may be necessary or expedient; (d) demolish the whole or part of any building or structure; (e) alter or remove any structure erected upon any highway or adjoining land; (f) alter, or alter the position of, railway track and any apparatus associated with railway track; (g) alter, or alter the position of, other apparatus, including mains, sewers, drains and cables; (h) alter the course of, or otherwise interfere with, non-navigable rivers, streams or watercourses; (i) carry out and maintain such other works, of whatever description, as may be necessary or expedient. (a) carry out and maintain landscaping and other works to mitigate any adverse effects of the construction, maintenance or operation of any of the works authorised by this Act, and (b) carry out and maintain works for the benefit or protection of land affected by any of the works authorised by this Act.[30]Section 2(1) refers to “Phase One purposes” which are defined in s.67 as follows:
“67. “Phase One purposes”
References in this Act to anything being done or required for “Phase One purposes” are to the thing being done or required— (a) for the purposes of or in connection with the works authorised by this Act, (b) for the purposes of or in connection with trains all or part of whose journey is on Phase One of High Speed 2, or (c) otherwise for the purposes of or in connection with Phase One of High Speed 2 or any high speed railway transport system of which Phase One of High Speed 2 forms or is to form part.” (a) for the purposes of or in connection with the works authorised by this Act, (b) for the purposes of or in connection with trains all or part of whose journey is on Phase One of High Speed 2, or (c) otherwise for the purposes of or in connection with Phase One of High Speed 2 or any high speed railway transport system of which Phase One of High Speed 2 forms or is to form part.”[31]Section 2(1) also refers to “the Act limits” which refers either to the limits of deviation for the scheduled works, or to the limits of land to be acquired or used, as shown on the deposited plans (s.68(2)).[32]Section 20 grants a deemed planning permission for the purposes of the TCPA 1990 for the carrying out of development authorised by the 2017 Act, that is to say scheduled works under s.1 and non-scheduled works under s.2:
“20. Deemed planning permission (1) Planning permission is deemed to be granted under Part 3 of the Town and Country Planning Act 1990 for the carrying out of development authorised by this Act. This is subject to the other provisions of this Act. (2) Where development authorised by this Act consists of the carrying out of a work which is not a scheduled work, subsection (1) does not apply if— (a) the development is likely to have significant effects on the environment by virtue of factors such as its nature, size or location, (b) the development is not exempt development within the meaning of the Environmental Impact Assessment Regulations, and (c) the development is not covered by an environmental assessment in connection with the High Speed Rail (London - West Midlands) Bill. (3) Schedule 17 imposes conditions on deemed planning permission under subsection (1). (4) … (5) …”
This is subject to the other provisions of this Act. (a) the development is likely to have significant effects on the environment by virtue of factors such as its nature, size or location, (b) the development is not exempt development within the meaning of the Environmental Impact Assessment Regulations, and (c) the development is not covered by an environmental assessment in connection with the High Speed Rail (London - West Midlands) Bill.[33]Ground 2 is concerned with the expression in s.20(2)(c) “the development is not covered by an environmental assessment in connection with” the Bill. That expression is defined by s.68(4) and (5):
“(4) For the purposes of this Act, development is covered by an environmental assessment in connection with the High Speed Rail (London - West Midlands) Bill if it is development in relation to which information contained in a deposited statement constituted, at the time of the statement's deposit or publication, an environmental statement within the meaning of the Environmental Impact Assessment Regulations. (5) Each of the following is a “deposited statement” for the purposes of this Act— (a) the statement deposited in connection with the High Speed Rail (London West Midlands) Bill in the Private Bill Office of the House of Commons in November 2013 in pursuance of Standing Order 27A of the Standing Orders of the House of Commons relating to private business (environmental assessment); (b) the statements containing additional environmental information published in connection with the High Speed Rail (London - West Midlands) Bill, notice of the publication of which was published in the London Gazette on 17 September 2014, 15 July 2015, 24 September 2015, 15 October 2015 and 7 December 2015.” (a) the statement deposited in connection with the High Speed Rail (London West Midlands) Bill in the Private Bill Office of the House of Commons in November 2013 in pursuance of Standing Order 27A of the Standing Orders of the House of Commons relating to private business (environmental assessment); (b) the statements containing additional environmental information published in connection with the High Speed Rail (London - West Midlands) Bill, notice of the publication of which was published in the London Gazette on 17 September 2014, 15 July 2015, 24 September 2015, 15 October 2015 and 7 December 2015.”
[34]Schedule 17 imposes conditions on the deemed planning permission under s.20 for works authorised under either s.1 or s.2 of the 2017 Act. The conditions require certain works to be approved by planning authorities subject to express restrictions on the extent of that control. In the present case the relevant conditions are contained in paras.2 and 3 of sched.17, which deal with “building works” and “other construction works” respectively.[35]Schedule 17 para.2, entitled “Condition relating to building works” includes the following provisions:
“(1) To the extent that development consists of building works, it must be carried out in accordance with plans and specifications for the time being approved by the relevant planning authority …. (5) If the relevant planning authority is a qualifying authority, it may only refuse to approve plans or specifications for the purposes of this paragraph on the ground that— (a) the design or external appearance of the building works ought to be modified— (i) to preserve the local environment or local amenity, (ii) to prevent or reduce prejudicial effects on road safety or on the free flow of traffic in the local area, or (iii) to preserve a site of archaeological or historic interest or nature conservation value, and is reasonably capable of being so modified, or (b) the development ought to, and could reasonably, be carried out elsewhere within the development's permitted limits. …. (7) The relevant planning authority may only impose conditions on approval for the purposes of this paragraph on a ground referred to in sub-paragraph (5) or (6) (as the case may be).”
NWBC is a “qualifying authority”. HS2L sought approval under condition 2 for plans and specifications for the BTEP and for a bridge. (a) the design or external appearance of the building works ought to be modified— (i) to preserve the local environment or local amenity, (ii) to prevent or reduce prejudicial effects on road safety or on the free flow of traffic in the local area, or (iii) to preserve a site of archaeological or historic interest or nature conservation value, and is reasonably capable of being so modified, or (b) the development ought to, and could reasonably, be carried out elsewhere within the development's permitted limits.[36]Schedule 17 para.3, entitled “Condition relating to other construction works” includes the following provisions:
“(1) If the relevant planning authority is a qualifying authority, development to which this paragraph applies must be carried out in accordance with plans and specifications for the time being approved by that authority. (2) This paragraph applies to development to the extent that it consists of the construction of any of the following— (a) a road vehicle park; (b) earthworks; (c) sight, noise or dust screens; (d) transformers, telecommunications masts or pedestrian accesses to railway lines; (e) fences or walls; (f) lighting equipment. …. (6) The relevant planning authority may only refuse to approve plans or specifications for the purposes of this paragraph on a ground specified in relation to the work in question in the following table. …. (7) The relevant planning authority may only impose conditions on approval for the purposes of this paragraph on a ground specified in the table in sub-paragraph (6) in relation to the work in question. …. (9) In this paragraph— “"construction”” includes erection, alteration, extension and (in the case of lighting equipment) installation; ““earthworks”” means terracing, cuttings, embankments or other earthworks; ….”
HS2L sought approval under condition 3 of plans and specifications for the Water Orton Cutting and “ancillary works”. (a) a road vehicle park; (b) earthworks; (c) sight, noise or dust screens; (d) transformers, telecommunications masts or pedestrian accesses to railway lines; (e) fences or walls; (f) lighting equipment.[37]Paragraphs 22 to 25 of sched.17 deal with appeals to the Secretaries of State against decisions by planning authorities on a request for an approval. Under para.22(1) HS2L may appeal to “the appropriate Ministers” against a decision of a planning authority on a request for an approval under inter alia paras. 2 or 3 of sched.17. By para.22(2) the appropriate Ministers may allow or dismiss the appeal or vary the decision of the planning authority, but they may only refuse an approval or impose conditions on an approval on grounds open to that authority under sched.17. If a planning authority does not notify HS2L of its decision on a request for approval within 8 weeks of receiving that request (subject to any extension agreed in writing), HS2L may appeal against a deemed refusal of approval (para.22(3) and (4)). In the present case HS2L appealed against a deemed refusal by NWBC.

EIA legislation

[38]When the Bill was deposited on 25 November 2013, Directive 2011/92/EU (“the EIA Directive”) was in force. Article 1(4) provided:
“This directive shall not apply to projects the details of which are adopted by a specific act of national legislation, since the objectives of this Directive, including that of supplying information, are achieved through the legislative process.”
[39]In R (Buckinghamshire County Council) v Secretary of State for Transport [2014] UKSC 3; [2014] 1 WLR 324 Lord Reed pointed out at [81]-[82] that the word “since” in art.1(4) had been interpreted by the Court of Justice of the European Union (“CJEU”) as meaning “provided that”. The objectives of the EIA Directive, including that of supplying information, had to be achieved through the legislative process. One of the main points argued by the claimants was that the delivery of Phase One of HS2 through the hybrid Bill procedure would breach the requirements laid down by the EIA Directive for EIA.[40]Lord Reed referred to the fundamental objective of the EIA Directive as being to ensure that projects likely to have significant effects on the environment are made subject to an “assessment” of their environmental effects before consent is given [84]. That assessment must be conducted on the basis of appropriate information supplied by the developer (including the ES), supplemented by information and representations provided by public authorities and members of the public concerned by the project in question [85].[41]The construction of a railway line for long-distance traffic is a project falling within Art. 4(1) and Annex I to the EIA Directive. In addition, para.13 of Annex II to the Directive provides:
“(a) Any change or extension of projects listed in Annex I or this Annex, already authorised, executed or in the process of being executed, which may have significant adverse effects on the environment (change or extension not included in Annex I); (b) … ”
The BTE and BTEP fell to be considered under para.13(a).[42]Where either a railway project falls within Annex I, or a change or extension to such a project would be likely to have significant adverse environmental effects, two consequences follow. First, such a project, must be subject to a requirement for development consent. Second, no such consent may be given before EIA of the project’s likely significant environmental effects in accordance with Arts.5 to 10 (Arts.2(1)), 4(1) and(2) and 8).[43]By Art.5 a developer is required to provide in an ES the information specified in Annex IV including a “description” of:• the site, design and size of the project (its physical characteristics and land use requirements during the construction and operational phases);• the aspects of the environment likely to be significantly affected by the project;• the likely significant effects of the project on the environment;• the measures envisaged in order to prevent, reduce and where possible offset any significant adverse effects on the environment;• a non-technical summary of the information provided.[44]Public authorities with relevant environmental responsibilities must have an opportunity to give their opinion on the information supplied under Art.5 and on its request for development consent (Art.6(1)). By Art.6(2) to (4) the public concerned must have an effective opportunity to make representations on the application for consent and the developer’s information and to participate in the environmental decision-making procedure. The above information and consultations must be taken into account in the development consent procedure (Art.8). When a decision is taken to grant or refuse development consent, the decision-maker must publicise not only the decision, but also the main reasons and considerations on which it is based, having examined the concerns and opinions expressed by the public, and the main measures for preventing or mitigating the major adverse effects of the project (Art.9(1)).[45]For projects requiring planning permission, the requirements of the EIA Directive were transposed by the Town and Country Planning (Environmental Impact Assessment) Regulations 2011 (SI 2011 No.1824) (“the 2011 EIA Regulations”) Although the 2011 EIA Regulations have subsequently been replaced by the 2017 EIA Regulations as from 16 May 2017, the 2017 Act received Royal Assent on 23 February 2017. Accordingly, the parties agree that the relevant regulations in force when the Bill was under consideration were the 2011 EIA Regulations (see also s.68(1) of the 2017 Act). They also agree that there are no material differences between the two sets of regulations for the purposes of dealing with the issues in this appeal. . Although the 2011 EIA Regulations did not in terms apply to a project which is to be authorised by a dedicated statute, the relevant Parliamentary Standing Orders applicable to the Bill adopted and adapted relevant parts of those Regulations for the proceedings in Parliament (see [48] below). It is also common ground that the objectives and requirements of the EIA Directive were applicable.[46]Regulation 3 of the 2011 EIA Regulations prohibited a decision-maker from granting planning permission in relation to “EIA development” without taking into consideration the “environmental information” on the project. That information included the ES, any further information supplied by the developer (under reg.22) and any representations by a consulted public authority or by the public (Reg.2(1)). Schedule 4 set out the requirements for an ES in similar terms to the EIA Directive (see [43] above). Part 5 of the 2011 EIA Regulations imposed requirements for consultation with relevant public bodies and publicity to enable the public to make representations both on the ES and on any further information which a developer was required to provide under reg.22. Regulation 24 imposed a duty on the decision-maker to publicise the decision on the application for permission and the basis on which it was made in line with the EIA Directive.[47]In Buckinghamshire County Council the Supreme Court held that the procedures in the Standing Orders for handling EIA development proposed in a Bill such as the hybrid Bill satisfied the requirements of the EIA Directive ([98]-[116]).[48]Lord Reed noted at [59] that Parliamentary Standing Orders had been made so that the legislative process would give effect to the objectives of the EIA Directive. For example, the Orders required that a Bill authorising the carrying out of works specified in that Bill be accompanied by an ES containing the information stipulated by the 2011 EIA Regulations. Copies of the ES had to be publicly available and the public were given the opportunity to make representations to the Minister responsible for the Bill. The Minister had to publish those comments and submit them to an independent assessor appointed by the Examiner of Petitions for Private Bills. The assessor had to prepare a report summarising the issues arising from those representations which was to be submitted to the House at least 14 days before second reading, for consideration by members. At third reading, the minister responsible had to set out the main reasons and considerations upon which Parliament was invited to approve the project and the main measures to avoid, reduce and if possible, offset its major adverse effects. A written statement dealing with those matters had to be laid before the House at least 7 days before third reading (see [60]). Thus the Parliamentary process gave effect to the key elements of EIA: the developer’s ES, the opportunity for public bodies and the public to make representations, taking those representations into account as part of the decision-making process and a statement of the main considerations for approving the project and dealing with mitigation.[49]The Supreme Court revisited the EIA regime in R (Finch) v Surrey County Council [2024] UKSC 20; [2024] PTSR 988. By this time Directive 2011/92/EU had been amended by Directive 2014/52/EU and the 2011 EIA Regulations replaced by the 2017 EIA Regulations. However, the relevant parts of the subsequent legislation are not materially different for present purposes.[50]EIA is essentially a “process” comprising the stages summarised by Lord Leggatt JSC at [15]:(1) the preparation of an ES by the developer;(2) the carrying out of consultations, including public consultation;(3) the examination by the decision-maker of the information received;(4) reasoned conclusions by the decision-maker for approving the project, taking into account the results of its examination. EIA exposes the environmental impact of a project to public debate and consideration in the decision-making process [3].[51]Lord Leggatt returned to this subject at [18]-[21]. The UK and the EU are parties to the Convention on Access to Information, Public Participation in Decision-Making and Access to Justice in Environmental Matters, known as the Aarhus Convention. The original EIA Directive in 1985 was amended to reflect obligations under that Convention. Recitals (16) and (19) of the EIA Directive state:
“(16) Effective public participation in the taking of decisions enables the public to express, and the decision-maker to take account of, opinions and concerns which may be relevant to those decisions, thereby increasing the accountability and transparency of the decision-making process and contributing to public awareness of environmental issues and support for the decisions taken. … (19) Among the objectives of the Aarhus Convention is the desire to guarantee rights of public participation in decision-making in environmental matters in order to contribute to the protection of the right to live in an environment which is adequate for personal health and well-being.”
Public participation is integral to the process of assessment [63].[52]A requirement to carry out EIA is not an indication that development consent will be or should be refused. Thus, at [62] Lord Leggatt said:
“It is also important to keep in mind that the legislation is essentially procedural in nature. It is not concerned with the substance of the decision whether to grant development consent but with how the decision is taken. Thus, as the House of Lords held in Berkeley, it is no answer to a challenge based on failure to carry out an EIA that complies with the EIA Directive to say that complying with the EIA Directive would not have affected the decision. It is essential to the validity of the decision that, before it is made, there has been a systematic and comprehensive assessment of the likely significant effects of the project on the environment in accordance with the EIA Directive.”
Likewise at [152]:
“The second, related flaw is also fundamental. The argument made is a version of the claim that, if information about environmental impacts would make no difference to the decision whether to grant development consent (or on what conditions), it is not legally necessary to obtain and assess such information in the EIA process. Such a contention was resoundingly rejected by the House of Lords in Berkeley [2001] 2 AC 603. It misunderstands the procedural nature of the EIA. The fact (if it be the fact) that information will have no influence on whether the project is permitted to proceed does not make it pointless to obtain and assess the information. It remains essential to ensure that a project which is likely to have significant adverse effects on the environment is authorised with full knowledge of these consequences.”

Principles of statutory interpretation

[53]A purposive approach should be adopted for the interpretation of legislation. As Lord Bingham said in R (Quintavalle) v Secretary of State for Health [2003] UKHL 13; [2003] 2 AC 687 at [8]: “The court’s task, within the permissible bounds of interpretation, is to give effect to Parliament’s purpose. So the controversial provisions should be read in the context of the statute as a whole, and the statute as a whole should be read in the historical context of the situation which led to its enactment.” “The purpose and scheme of an Act of Parliament provide the basic frame of orientation for the use of the language employed in it” (R (PACCAR Inc) v Competition Appeal Tribunal [2023] UKSC 28; [2023] 1 WLR 2594 per Lord Sales JSC at [41]).[54]In CG Fry and Son Limited v Secretary of State for Housing, Communities and Local Government [2025] UKSC 35, [2025] PTSR 1823 Lord Sales stated at [46] that in that case:
“There was no dichotomy between looking at the natural and ordinary meaning of legislation and a purposive approach to construction. The authorities make it clear that the correct approach is that legislation must be construed having regard to its context and in the light of its purpose.”
[55]In R (O) v Secretary of State for the Home Department [2022] UKSC 3; [2023] AC 255 Lord Hodge DPSC stated at [29]: “Words and passages in a statute derive their meaning from their context. A phrase or passage must be read in the context of the section as a whole and in the wider context of a relevant group of sections. Other provisions in a statute and the statute as a whole may provide the relevant context. They are the words which Parliament has chosen to enact as an expression of the purpose of the legislation and are therefore the primary source by which meaning is ascertained.…” (see also PACCAR at [42]).[56]Lord Hodge continued at [30]:
“External aids to interpretation therefore must play a secondary role…. The context disclosed by such materials is relevant to assist the court to ascertain the meaning of the statute, whether or not there is ambiguity and uncertainty, and indeed may reveal ambiguity or uncertainty…. But none of these external aids displace the meanings conveyed by the words of a statute that, after consideration of that context, are clear and unambiguous and which do not produce absurdity.”
[57]In R (Edison) v Central Valuation Officer [2003] UKHL 20; [2003] 4 All ER 209 Lord Millett addressed at [116] the interpretative presumption that Parliament intended to act reasonably in passing legislation:
“… The court will presume that Parliament did not intend a statute to have consequences which are objectionable or undesirable; or absurd; or unworkable or impracticable; or merely inconvenient; or anomalous or illogical; or futile or pointless. [117] But the strength of these presumptions depends on the degree to which a particular construction produces an unreasonable result. The more unreasonable a result, the less likely it is that Parliament intended it…”
[58]It is assumed that when Parliament legislates, it knows relevant existing law. (Hirachand v Hirachand [2024] UKSC 43; [2025] AC 599 at [58]). In the present case it should be assumed that s.20 was enacted in the knowledge of EIA legislation and case law, including the decisions in the Buckinghamshire case and R v Rochdale Metropolitan Borough Council ex parte Milne [2001] Env. L.R. 406 (see below [87] and [131] et seq).

The Environmental Minimum Requirements

[59]HS2L entered into a development agreement with the Secretary of State for Transport on 8 December 2014 (amended on 17 July 2017). Under the agreement HS2L is contractually bound to comply with the Environmental Minimum Requirements (“EMRs”).[60]In February 2017 the Department for Transport published “Environmental Minimum Requirements – General Principles”. The Secretaries of State referred in their submissions to para.1.1.3. which states:
“The controls contained in the EMRs, along with powers contained in the High Speed Rail (London - West Midlands) Act (the Act) and the Undertakings given by the Secretary of State, will ensure that impacts which have been assessed in the ES will not be exceeded, unless any new impact or impacts in excess of those assessed in the ES: • results from a change in circumstances which was not likely at the time of the ES; or • would not be likely to be environmentally significant; or • results from a change or extension to the project, where that change or extension does not itself require environmental impact assessment (EIA) under either (i) article 4(1) of and paragraph 24 of Annex 1 to the EIA Directive; or (ii) article 4(2) of and paragraph 13 of Annex 2 to the EIA Directive; or • would be considered as part of a separate consent process (and therefore further EIA if required).”
(emphasis added) They also referred to para.3.6.1. of Annex 4 to the EMRs. • results from a change in circumstances which was not likely at the time of the ES; or • would not be likely to be environmentally significant; or • results from a change or extension to the project, where that change or extension does not itself require environmental impact assessment (EIA) under either (i) article 4(1) of and paragraph 24 of Annex 1 to the EIA Directive; or (ii) article 4(2) of and paragraph 13 of Annex 2 to the EIA Directive; or • would be considered as part of a separate consent process (and therefore further EIA if required).” (emphasis added)[61]Paragraph 1.1.3. acknowledges that the EMRs do not ensure that impacts assessed in the ES for the Bill will not be exceeded. There may be such exceedances where new impacts inter alia result from a change in circumstances which was not likely at the time of the ES for the Bill, or would be considered as part of a separate consent process requiring EIA. That last point begs the question raised in this appeal about the scope of s.20(2) of the 2017 Act.[62]In addition, the third bullet point in para. 1.1.3. leaves open the possibility that impacts assessed in the ES may be exceeded, notwithstanding the EMRs, where a change or extension of a project has significant adverse environmental effects falling within para.13 of Annex II (see [41] above). No doubt the draftsman of the 2017 Act had well in mind the Buckinghamshire case and the need for that legislation and eh Parliamentary process followed to be compatible with the EIA Directive.[63]The Secretaries of State also refer to the undertaking given by the SST to Parliament that in so far as the EMRs are not directly enforceable against HS2L, the SST “will take such steps as he considers reasonable and necessary to secure compliance with those requirements”.[64]The EMR principles summarised in [60] above do not preclude environmental impacts exceeding those assessed in the ES in all circumstances. In any event, the EMRs do not form part of the statutory scheme. Indeed, in R (Hillingdon London Borough Council) v Secretary of State for Transport [2020] EWCA Civ 1005; [2021] PTSR 113 the Court of Appeal held at [43] that “nothing in an EMR is capable of mandating or authorising something not permitted under, or inconsistent with, the Act, including its Schedules”. Consequently, the EMRs are not capable of altering the system of statutory control in sched.17 of the 2017 Act [76] nor, I would add, the scope of the deemed planning consent in s.20 or its interaction with EIA legislation.[65]Furthermore, there has been no suggestion that the EMRs are enforceable by any party other than the SST, for example a LPA. The SST’s undertaking was given to Parliament and the accountability of the SST in relation to it is solely a matter for Parliament. In any event, the undertaking allows the SST a substantial measure of discretion as to the extent to which he will secure compliance with the EMRs.[66]Accordingly, neither the EMRs nor the undertaking provide any real assistance to the court on the issues of construction of the 2017 Act (and its interaction with the EIA regime) which the court is asked to resolve. I should also record that we have not been shown any extract from Hansard which would be admissible under Pepper v Hart [1993] AC 593 as an aid to interpretation of the legislation.[67]Nevertheless, HS2L said that the objective of the EMRs was one source for the approach it took to the handling of the proposal for the BTE, the subject to which I turn next.

The handling of the proposal for the BTE and BTEP

[68]Mr. Paul Gilfedder is the Head of Town Planning at HS2L. In his witness statement he explains that Volume 2 of the ES was divided into reports on 26 areas (“Community Forum Areas”) covering the whole route of Phase One. Each report addressed the likely significant environmental effects of the project in the relevant area. The assessment included illustrative drawings showing the land potentially required during construction, the main construction, permanent features and areas for landscaping and mitigation. The ES assessed the reference design for Phase One as it was at the time of the Bill and any differences to the likely significant effects and mitigation if “the scheme” were to be built within the limits of deviation. But the assessment excluded changes considered “unlikely or impossible” (para.7.6).[69]The original scheme presented to Parliament required the diversion of the River Tame which ran along 700m of the railway route, the construction of a viaduct over the river, the construction of three bridges, the realignment of a lane and the construction of a number of retaining walls (Gilfedder paras.8.2 to 8.3). The railway would have emerged at the eastern portal at the Castle Bromwich Business Park affecting businesses there, and it would have affected the River Tame, a nature conservation site, a primary school and residential properties in Water Orton (para.8.5).[70]The revised scheme relocated the eastern portal from the Business Park and so avoided the demolition of commercial properties. It also made it unnecessary to realign the River Tame, reduced ecological impact to several habitats, and reduced visual impact (e.g. by removing the viaduct). But the revised scheme required a shaft to be built at Castle Bromwich and the construction of the portal at Water Orton along with a control building. It has also increased the duration of civil engineering works from 3.5 years to 5 years and required tunnelling to be carried out for 24 hours a day (Gilfedder paras.9.8 to 9.9). In her first witness statement, Ms. Erica Levy, the Development Control Manager for NWBC identified additional impacts which she says have not been assessed.[71]At the beginning of 2021 it appears that HS2L was of the view that the BTE could not be constructed under s.2 of the 2017 Act. The company proposed to seek a TWAO to authorise the whole of the extension to the tunnel.[72]Accordingly, in February 2021 HS2L submitted to the SST a “Screening Report” to obtain the Secretary of State’s decision on whether the BTE was required to be the subject of EIA under the regime then in force, as a change or extension of a project already authorised likely to have significant adverse effects on the environment. To address that issue, the Screening Report compared the proposed BTE with the scheme assessed in the Phase One ES deposited in 2013, in order “to determine whether the proposed development is likely to have new or different adverse significant effects on the environment, by virtue of factors such as its nature, size or location”. The Secretaries of State submitted to us that this approach accorded with the EMRs.[73]HS2L’s report opined that “following mitigation, there are no new or different likely adverse significant environmental effects caused by the proposed development” and therefore an additional EIA was not required. After the introductory sections explaining HS2L’s approach, the full report addressed environmental impacts relating to 16 subjects over some 230 pages.[74]NWBC responded to HS2L’s screening report in a letter dated 10 March 2021. The Council’s overall conclusion was that there would be “no new or different likely adverse significant adverse effects caused by the proposed development” and therefore no additional EIA was required. However, NWBC referred to greater local impacts at Water Orton in the vicinity of the relocated eastern portal in terms of both construction and operation. Given the greater amount of development in that area, the authority considered that there would be insufficient scope to landscape and screen this part of the project. Jumping ahead to the Inspector’s report, I note that he came to the same conclusion (IR 43 – IR 47 and Addendum IR 14-16).[75]The SST’s formal response to the screening report was issued on 31 March 2021. The Secretary of State’s legal approach to the question of whether further EIA was required differed from that of HS2L’s screening report. “The Secretary of State notes the EIA Screening Report attached to your request concludes that the project, if amended as proposed, would not result in any new or different significant environmental effects as compared against the existing consented project and it therefore does not need to be subject to EIA. However, the Secretary of State considers that the necessary consideration is whether the project, to which the proposed Order would apply, is EIA development or not. The project would be EIA development if it falls within paragraph 13 of Annex II to the EIA Directive i.e. “Any change or extension of projects listed in Annex I or [Annex II] already authorised, executed or in the process of being executed, which may have significant adverse effects on the environment (change or extension not included in Annex I)”. As acknowledged in the EIA Screening Report, the proposed changes to the project are likely to have significant effects on the environment (even if these are no greater than those previously assessed). The Secretary of State therefore considers that the development that would be subject to the proposed Order falls within paragraph 13 of Annex II. Therefore, in accordance with rule 7(13) of the above Rules, the Secretary of State’s screening decision is that an environmental impact assessment is required in relation to the Bromford Tunnel Extension Scheme which is to be the subject of the above proposed Order.” (original emphasis) In effect the legal approach taken by the SST at that stage is consistent with the NWBC’s stance under ground 2 and inconsistent with that of the respondents and the judge.[76]The Inspector said in his report to the Secretaries of State that one of the main issues was whether some or all of the application works benefited from the deemed planning consent under s.20 of the 2017 Act. In so far as they did not, the application procedure in sched.17 would not be applicable and an express grant of planning permission would be required.[77]NWBC submitted to the Inspector that the BTE and eastern portal were not authorised works under s.2 of the 2017 Act and were not permitted by the s.20 consent. In contrast to its letter dated 10 March 2021 (see [75] above) the Council now took the view that the BTE and portal would be likely to have significant environmental effects (IR 19 to IR 20).[78]HS2L contended that the development was authorised by s.2 of the 2017 Act. It benefited from the s.20 permission because(1) it would not have significant effects on the environment and (2), and in any event, it was “covered by” the environmental assessment undertaken for the Bill (IR 28). HS2L relied upon its letter to NWBC dated 22 June 2021, in which that second point was expressed in the following various ways: (1) The works would be compliant with the EMRs;(2) The works would be within the wider “envelope” of impacts set out in the original “HS2 Environmental Statement”;(3) Any changes in connection with the BTE needed to be assessed against the base case assessment for the ES in connection with the Bill. “If there is the likelihood of any new or different significant effects arising (whether as a result of changes to the scheme such as repositioned/additional features/changed mitigation) which have not been assessed in the Phase One ES then consideration would need to be given to deferring those elements of works.”(4) “The deemed planning permission under section 20 will only apply in so far as HS2 can demonstrate that these works will not generate new or different environmental impacts beyond what has been assessed in the ES”.[79]The Inspector concluded first that the BTE and portal did not fall within the powers in s.2 to carry out non-scheduled works (IR 38 to IR 40). Second, he concluded that the deemed planning permission under s.20 did not apply to those works. That was because he considered that the works would be likely to have significant effects on the environment (s.20(2)(a) of the 2017 Act and see IR 43 to IR 45 and IR 47) and they had not been subject to EIA as part of the process relating to the Bill. The ES had stated that the BTE had not been included in the proposed scheme. The scheduled works authorised by s.1 of the 2017 Act had been considered to have the greatest environmental benefits in comparison to other options (s.20(2)(c) and IR 41 to IR 43 and IR 47).[80]Disagreeing with the Inspector the Secretaries of State concluded(1) that the BTE and portal were works authorised by s.2 of the 2017 Act and(2) the permission in 20(1) applied to those works. In relation to that second issue they stated at DL 10 to DL 13: “10. The Inspector found that as an environmental assessment for the BTE was not reported on in the original ES he was not persuaded that a portal associated with the proposed BTE should be looked upon as benefitting from the DPP (IR43). 11. The Secretaries of State disagree with this conclusion. They find that for the purposes of sub-section (2)(c) of Section 20 development is “covered by an environmental assessment in connection with the High Speed Rail (London – West Midlands) Bill” where there are no new or different likely significant effects to those reported in the environmental assessment. The Secretaries of State do not agree that sub-section (2)(c) should be construed as excluding any development which differs from the detailed description set out in the ES which was placed before Parliament. 12. The interpretation favoured by the Secretaries of State is supported by the Environmental Minimum Requirements (EMRs) and the HS2 Information Paper E1: Control of Environmental Impacts. These were published in draft during the passage of the HS2 Bill, and published in final form about the time of Royal Assent. The EMRs state that the intention of the provisions of the HS2 Act and the EMRs is to ‘ensure that impacts which have been assessed in the ES will not be exceeded’. The Secretaries of State therefore consider that development where there are no new or different likely significant effects to those reported in the ES can fall within sub-section (2)(c). When read in their proper context, sections 20(2)(c) and 68(4) of the HS2 Act should be regarded as bringing within the ambit of the DPP those works which would not result in new or different likely significant effects to those assessed in the ES. 13. The Secretaries of State note that the BTE now proposed is longer and the BTEP is in a different location to that assessed in the ES which was placed before Parliament. However, the Secretaries of State are mindful that, as recorded at IR19, in February 2021 the appellant made an Environmental Impact Assessment (EIA) screening request for the revised scheme. Accordingly, the BTE and the relocation of the BTEP is not a scheduled work, but does not introduce any new or different likely significant effects to those assessed in the ES. In reaching this conclusion the Secretaries of State have had regard to the matters referred to in the IR and AR (including at IR41, IR 45, Addendum IR16 and Addendum IR23) as potential environmental effects of the proposals, but conclude that none of these matters amount to a new or different likely significant effect to those assessed in the ES.” (original emphasis) It is common ground that the passage cited in DL 12 from the EMRs is taken from para.1.1.3. of “Environmental Minimum Requirements: General Principles” (see [60] above).[81]However, the Secretaries of State did not disagree with the Inspector that the test in s.20(2)(a) of the 2017 Act was satisfied, namely, that the BTE and portal were likely to have significant environmental effects. They decided that the s.20 planning permission applied to those works solely because of the construction they adopted for s.20(2)(c). They also decided that the test under that provision was whether the likely significant effects of the BTE and BTEP would or would not be different or new as compared with those assessed during the Bill process for the same section of the project. As I explain below, what the respondents meant by this was that those effects should be no greater than those assessed in the EIA for the Bill.

The judgment of the High Court

[82]The judge said that he would apply the unified approach to statutory construction upon which the parties agreed: the language of the legislation is to be read and understood in its context and in the light of its purpose [28].[83]On ground 1, the judge held that the BTE and portal were authorised by s.2 of the 2017 Act. Sections 1 and 2 are complementary to each other. Parliament recognised that the scale and nature of the project made it necessary for some details to be determined after the enactment of the 2017 Act as part of the working up of the design. The legislation provides for “constrained flexibility”. That flexibility is constrained by the purposes for which the works may be carried out, the limits of deviation and the limitations of the works permitted by sub-paras. (a) to (i) of s.2(1) ([31] to [34]). Furthermore, such works do not benefit from the deemed grant of planning permission if they fall within the exceptions (a) to (c) in s.20(2) of the 2017 Act [37].[84]Section 2(1) grants authority for the construction of a wide range of works, some on a significant scale, and uses particularly wide language. Parliament had not seen fit to exclude tunnels from those provisions [36]. “Phase One purposes” include those broadly defined in s.67(c) [38]. The 2017 Act did not contain any indication that a tunnel could only be authorised under s.1 as a scheduled work [39]. The statement in the Explanatory Notes for the 2017 Act that s.2(1) allows the carrying out of ancillary works cannot circumscribe the broad language which Parliament chose to use in s.2 [40].[85]The judge concluded that the BTE and portal fell within s.2(1) of the 2017 Act, without needing to rely upon the generic provisions in the Railway Clauses Consolidation Act 1845 or the Railway Clauses Act 1863 [41].[86]On ground 2 the judge considered that the NWBC’s submissions focused simply on the language of s.20(2)(c) and s.68(4), rather than the context in which those provisions sit, namely the wider framework of the legislation and jurisprudence relating to EIA. “Covered by an environmental assessment” is to be understood by reference to the legal principles governing the operation of the EIA regime [46].[87]In particular, the judge based his analysis on the principles laid down by Sullivan J (as he then was) in Milne to deal with projects the description of which is not fixed at the outset and which need to incorporate a degree of flexibility ([46] to [47]). The 2017 Act provides the framework for the project of constructing and maintaining the railway and the ES for the Bill examined the likely significant environmental effects of that project. If a proposed work under s.2(1) would not give rise to effects beyond those which have already been the subject of assessment in the ES, then that work would be “covered” by it [48]. The judge went on to say at [49] that works under s.2(1) “will be within the scope of the project which has been the subject of Environmental Impact Assessment if they would not give rise to any likely significant effects greater than those which had been assessed in the environmental statement”.

The judge then said this at [50]:

“It follows from this understanding of the legislative framework, read in context, that the claimant’s interpretation, which would require every feature of the development to be specifically identified and contained within the deposited environmental statement, does not reflect the process of Environmental Impact Assessment necessary to give rise to compliance with the Environmental Impact Assessment legislation. It is not necessary for an individual work within the power provided by section 2(1) to have been specified and then subject to assessment in the environmental statement. What is necessary is for work not to give rise to likely significant effects which have not been the subject of assessment in the environmental statement process. In my view, the use of the word “covered” clearly contemplates that there would be non-scheduled works which could not be specified at the time of the Act passing but which could be brought forward pursuant to the power in section 2(1) and which could be subject of deemed planning permission provided they were within what is often referred to as the environmental envelope provided for in the environmental statement.”
[89]The judge said that the above reasoning was sufficient to dispose of ground 2 [52], but he went on to add that various HS2 papers which accompanied the passage of the Bill through Parliament, such as “Environmental Minimum Requirements – General Principles” were consistent with the interpretation of s.20 which he adopted ([53] to [56]).[90]Having decided that the interpretation by the Secretaries of State of s.20 was correct, the judge held that the issue of whether or not the BTE would give rise to new or different significant effects as compared with the ES for the Bill was a matter of evaluative judgment for those decision-makers. That judgment could not be impugned ([59] and [62]).

Ground 1

[91]In summary, the appellant made the following submissions:(1) A proper understanding of the scope of s.1 is necessary to the construction of s.2. The power to construct the railway defined in s.1(3) is contained in s.1(1) of the 2017 Act;(2) About 20% of the route will run through tunnels. All of those tunnels, apart from the BTE, are scheduled works, described in sched.1;(3) Where the 2017 Act intends to authorise the construction of a tunnel (or a viaduct) it does so explicitly. The wording and scheme of the Act shows that Parliament only authorised tunnels to be constructed as scheduled works and not as non-scheduled works under s.2;(4) Section 2 only permits works which are ancillary to the scheme authorised by s.1. Paragraph 19 of the Explanatory Notes to the 2017 Act states that s.2(1) allows the undertaker to carry out “ancillary works”. The statutory guidance under para.26 of sched.17 given by the Secretary of State for Transport to planning authorities on the exercise of their functions under that schedule also supports this interpretation;(5) Section 2(1)(a) to (h) describe works which are ancillary to the scheduled works under s.1. Those sub-paragraphs describe works which are to be carried out in order to receive or accommodate “the scheme itself”;(6) The language of s.2(1)(i) should not be interpreted so broadly as to render s.2(1)(a) to (h) redundant. In addition the ejusdem generis principle applies so as to restrict the ambit of s.2(1)(i);(7) The authority under s.2(1) to carry out works “for Phase One purposes” is also limited to ancillary matters. The language used does not authorise an amendment of the scheme itself, in the sense of the scheduled works. Those works have been fixed by the 2017 Act. Paragraph 1(1) of sched.1 imposes an obligation on the undertaker to construct the scheduled works within the lines, levels and situations so shown. The flexibility which the 2017 Act allows for the construction of scheduled works is restricted to the limits of deviation (para.1(2) of sched.1).[92]Section 1 of the 2017 Act relates to the works which are specified in sched.1. But I note that those works are not confined to works for the construction of the railway defined in s.1(3). They also include works “consequent on, or incidental to” the building and operation of that railway.[93]In addition, Parliament also recognised that, given the scale and complexity of the project, and the stage it had reached by the time of enactment, the powers in s.2 were required to respond to the further design work which would be necessary subsequently. Such design work would be expected to identify the need for additional or amended engineering features or structures falling outside the scheduled works specified in sched.1.[94]Paragraph 1(1) of sched.1 does not impose an obligation on HS2L to construct all of the scheduled works. It has to be read compatibly with s.1, which creates a power to construct the railway, not a duty. The effect of para.1(1) of sched.1 is that if, and in so far as, the power to construct the scheduled works is exercised, those works can only be carried out in accordance with the deposited plans and the other parameters specified. Those provisions do not preclude the possibility of additional works being carried out under s.2. They do not provide that the railway described in s.1(3), and its constituent parts, may only be built under s.1(1). If, for example, the BTE is a work authorised by s.2, the 2017 Act does not provide that it is unlawful because it would involve a failure to build a scheduled work under s.1 for that same section of the railway. The true questions are what is the meaning of s.2 and does the BTE fall within its ambit?[95]Section 2 does not contain any express language restricting the works authorised thereunder to works ancillary to a scheduled work (or works).[96]The list of items set out in sub-paras. (a) to (h) does include items of an ancillary nature, such as the demolition or alteration of buildings and structures and alterations to apparatus associated with a railway track. But it also includes works which may form part of the railway itself, but which were not specified in sched.1. Examples include embankments, abutments, retaining walls, bridges, shafts, buildings and other “necessary or expedient” works. Such works may form an integral part of the railway and need not simply be items ancillary to scheduled works.[97]I do not attach any significance to para.19 of the Explanatory Notes on the 2017 Act as an aid to the construction of s.2. It simply says that ancillary works may be carried out under s.2 and that subsections (1) and (2) outline the types of works which may be carried out. It does not purport to be a complete explanation of s.2(1). It does not suggest that that provision is restricted to ancillary works. In any event, the Explanatory Notes we have been shown are those which accompanied the statute, and not those notes (if any) which accompanied the Bill and were available to be considered by Parliament. In Adriatic Land 5 Limited v Long Leaseholders at Hippersley Point [2025] EWCA Civ 856; [2026] 1 WLR 1857 Newey LJ referred to the authorities which explain that distinction and said that Explanatory Notes published by a Government department post enactment do not enjoy any particular legal status. They may be compared with academic writings ([65]-[72]).[98]The statutory guidance to planning authorities on their functions under sched.17 of the 2017 Act is of no assistance at all. It was not the function of the document to offer a commentary on section 2 of the Act, nor did it purport to do so. Its references to ancillary works have nothing to do with the question whether the ambit of s.2 is limited to such works.[99]I do not think that either of the two canons of construction relied upon by the appellant (see [91(6)] above) support ground 1. Such canons may be useful “as guidelines rather than railway lines”. Although they embody logic or common sense, they exist to illuminate and help, but not to constrain or inhibit (Lord Neuberger of Abbotsbury PSC in Cusack v Harrow London Borough Council [2013] UKSC 40; [2013] 1 WLR 2022 at [57]-[60]).[100]There may be a reason why Parliament enacts specific provisions followed by a broad provision, so that giving effect to that broad language does not render that specific language otiose. This may depend upon the nature of the language used and its context. Here, s.2(1) begins with the purposes for which the power may be used, followed by a list of specific instances where those purposes may be satisfied (sub-paras (a) to (h), concluding with the general provision in sub-para (i)). Sub-paragraphs (a) to (h) list items which are capable of falling within s.2(1) in any event. Sub-paragraph (i) has been included because, unsurprisingly, Parliament did not seek to envisage for such a large and complex project all the various types of work which might fall within sub-paras. (a) to (h). Accordingly, the broad language of sub-para (i) does not render any of sub-paras. (a) to (h) otiose. That conclusion holds good even if sub-para (i) is not read as limited to ancillary works (Bennion, Bailey and Norbury on Statutory Interpretation (9th ed) contains a helpful discussion in sections 17.4 and 21.2).[101]The appellant gains no support from the ejusdem generis principle. If a genus cannot be identified, there is no room for the principle to be applied (Bennion at section 23.3). In S.S. Magnhild v MacIntyre Brothers and Company [1920] 3 KB 321 McCardie J held at p.330 that the specific provisions must belong to some common category, possessing “some common and dominant feature”. Here the appellant submitted that the genus common to s.2(1)(a) to (h) were works falling outside s.1 of the 2017 Act which are ancillary to one or more scheduled works. But, as I have said, there is nothing in s.2(1) to indicate that the items in sub-paras. (a) to (h) are limited to works ancillary to works within sched.1, or works which accommodate or receive such works. Some of the terms used in those sub-paragraphs refer to works which may or may not be ancillary in the sense used by the appellant. Some of those terms could include works forming part of the railway itself.[102]At this point we arrive at a major flaw in the appellant’s case on ground 1. Section 2(1)(i) is drafted in broad terms so as to cover “such other works, of whatever description as may be necessary or expedient”. The words I have emphasised could hardly be wider. The word “expedient” simply means suitable. Works within s.2(1)(i) must serve one of two functions laid down at the beginning of the subsection:
“for the purposes of or in connection with the scheduled works” or “otherwise for Phase One purposes”
. If Parliament had intended to restrict non-scheduled works within s.2(1) to works ancillary to scheduled works in s.1, why did it add the words “or otherwise for Phase One purposes”? The appellant did not have any real answer to that question. The definition in s.67 of those purposes includes:
“… or, (c) otherwise for the purposes of or in connection with Phase One of High Speed 2 or any high speed railway transport system of which Phase One of High Speed 2 forms or is to form part.”
Thus, a non-scheduled work within s.2(1) does not have to be ancillary to a scheduled work within s.1. It may be for “the purposes of” Phase One, that is the railway described in s.1(3) of the 2017 Act.[103]Given the breadth of the language in s.2(1) and the substantial nature of the works that may be carried out thereunder, the absence of the word “tunnel” is of no consequence. Likewise the express mention of “tunnel” in para.30 of sched.17 casts no light on the ambit of s.2(1), or on whether a tunnel is capable of falling within that provision. Paragraph 30 excludes a number of items, including “any tunnel”, from the definition of “building” for the purposes of the planning control under sched.17 applicable to “building works”. That system of control applies to the deemed planning permission for works falling within both sections 1 and 2 (subject to the exclusion of certain non-scheduled works by s.20(2)). It tells us nothing about the meaning of s.2(1).[104]Accordingly, I agree with the judge’s conclusion that the BTE is authorised by s.2(1) of the 2017 Act. The BTE constitutes works necessary or expedient for the purposes of or in connection with the “scheduled works” or “otherwise for Phase One purposes”. Having reached that clear conclusion, I agree with the judge that there is no need to delve into the Railway Clauses Consolidation Act 1845 or the Railway Clauses Act 1863.[105]For the above reasons, ground 1 must be rejected.[106]Although the language of s.2(1)(i) of the 2017 Act is broad there are significant constraints. First, the works must be for the purposes of or in connection with the scheduled works, or they must be for “Phase One purposes” as defined in s.67. Second, those works must lie within “Act limits”, that is the limits of deviation, or the land to be acquired or used under the Act. Third, if the works benefit from the deemed planning permission under s.20(1), that permission is subject to the conditions imposed by s.20(3) and sched.17. So the approval of the relevant planning authority may be required for certain plans and specifications. Fourth, if the works are non-scheduled and are likely to have significant effects on the environment they will not have the benefit of the deemed planning consent if they fall within s.20(2)(c) (i.e. the development is not covered by an environmental assessment in connection with the Bill). In that event, HS2L would need to obtain a planning permission, subject to the EIA process being satisfied. This brings me to ground 2.

Ground 2

[107]Scheduled works have the benefit of the deemed planning permission in s.20(1) but are subject by virtue of s.20(3) to the conditions in sched.17 which provide for a limited degree of planning control. Scheduled works will have been the subject of EIA in accordance with Parliamentary Standing Orders. For that reason the provisions in s.20(2) for disapplying the deemed planning permission do not apply to scheduled works.[108]In the case of non-scheduled works authorised by s.2(1) of the 2017 Act, s.20(2) disapplies the deemed planning permission in s.20(1) only if “the development” falls within all three of the criteria in sub-paras. (a) to (c). They are three separate tests and are not to be conflated.[109]Sub-paragraph (a) reproduces the test in the EIA Directive and the 2011 EIA Regulations for deciding whether a development requires EIA,: that is whether it would be likely to have significant environmental effects. But by sub-para. (b) such development has the benefit of the deemed planning permission if it is “exempt development” with the meaning of the 2011 EIA Regulations. Finally, the effect of s.20(2)(c) is that development falling within s.20(2)(a) (and for which EIA would ordinarily be required), nevertheless benefits from the deemed planning permission if that development is “covered by an environmental assessment” in connection with the Bill. But if that development falls within s.20(2)(c) (i.e. it is not so covered), and also within s.20(2)(a) and (b), then planning permission and EIA are both required. It is clear that the purpose of section 20(2) is to ensure that non-scheduled works authorised by the 2017 Act are not carried out in breach of the 2011 EIA Directive.[110]Three things about s.20(2)(c) are plain. First, it is to be understood in the context of the EIA Directive and the 2011 EIA Regulations. Second, s.20(2) was included in the 2017 Act as part of a statutory scheme designed to satisfy the objectives and requirements of the EIA Directive (see [38]-[44] and [47]-[52] above). Third, in relation to non-exempt, non-scheduled development likely to have significant environmental effects, s.20(2)(c) should be interpreted, so far as possible, to give effect to the EIA Directive, including the requirement for EIA to be undertaken in relation to those effects and the mitigation of those effects.[111]Some matters are uncontroversial:(1) As the Inspector recorded at IR 41, HS2L accepts that the BTE and revised portal were not included in the EIA for the Bill;(2) So long as the decision-maker interprets s.20(2)(c) correctly, the application of that provision is a matter for his or her evaluative judgment;(3) This appeal does not involve any challenge to the rationality of the judgment reached by the Secretaries of State in this case or to the legal adequacy of the reasons given;(4) The sole challenge raised by the appellants is that the Secretaries of State misinterpreted s.20(2)(c) and therefore used the wrong legal test when applying that provision.[112]But what was the approach which the Secretaries of State took? Their decision letter of 14 May 2024 was based upon HS2L’s EIA Screening Report of February 2021. That Report had accompanied a request made by HS2L to the SST for a screening decision on whether the application then proposed to be made for a TWAO, which included both the BTE and portal, had to be the subject of EIA (see [71]-[76] above). The s.17 application which HS2L subsequently made to NWBC in September 2021, and HS2L’s appeal to the Secretaries of State against a deemed refusal of that application, formally sought approval for the portal but not the BTE. But plainly, the portal could not be constructed 2.9km to the east of the location authorised by the 2017 Act unless the tunnel were to be extended to that point. Accordingly, the decision letter in May 2024 considered whether s.20(2)(c) applied to both the BTE and the revised portal.[113]The test advanced by HS2L in its Screening Report in February 2021, and ultimately adopted by the Secretaries of State in their decision letter of 14 May 2024, was whether the tunnel extension and new portal would result in “any new or different significant environmental effects” (see DL 12 – DL 13).[114]However, the 2017 Act had been enacted on the basis that the Parliamentary process and the authorisation for development it conferred complied with the EIA Directive, including para.13(a) of Annex II (and also their equivalents in the 2011 EIA Regulations). Accordingly, if the BTE and portal were likely to have significant adverse environmental effects (the test contained also in s.20(2)(a)), EIA was required to be undertaken for that development (subject also, of course, to s.20(2)(c)). That was the legal approach to the Directive which the SST had taken in his decision on 31 March 2021 when he rejected the “new or different significant environmental effects” test (see [75] above). At that stage the SST concluded that:(1) The issue was whether the proposal to alter the project was for “EIA development” or not;(2) The proposal would be EIA development and require EIA if it fell within para.13(a) of Annex II to the EIA Directive (see [41]-[42] above). In other words the test was whether the changes to the project were likely to have significant adverse environmental effects;(3) HS2L’s Screening Report of February 2021 acknowledged that the proposed changes would have such effects, “even if they were no greater than those previously assessed”;(4) Accordingly, the changes fell within para.13(a) of Annex II and EIA was required. It also follows from the reasoning of the SST that the works fell within s.20(2)(a) of the 2017 Act, which was also the position taken by the Inspector and one from which the decision letter of 14 May 2024 did not move (see [75], [79] and [81] above).[115]There is no disguising the fact that the SST has not explained how he moved from his clear reasoning in March 2021 on the EIA Directive and his rejection of HS2L’s approach in its Screening Report to his acceptance of that approach in the joint decision letter of 14 May 2024. Although the letter referred to that Report, it did not refer to the screening decision which resulted. The decision letter addressed s.20(2)(c) of the 2017 Act, but it is s.20(2) as a whole which was meant to secure compliance with the objectives and requirements of the EIA Directive and they had not changed materially since March 2021.[116]The clear implication of the screening decision on 31 March 2021 was that the environmental effects of the BTE and revised portal were different, even if viewed overall they were “no greater than those previously assessed”. Indeed, it is obvious from the assessment in the Screening Report accepted by the respondents that the effects were different. The revised scheme reduced or avoided some of the environmental effects of the scheduled works for this section of the railway line. For example, it did not require the demolition of properties in a business park, or the diversion of the River Tame, its ecological impact was reduced and the section of railway line in the BTE would be concealed below ground. On the other hand, the revised scheme caused different adverse environmental effects at the eastern end of the BTE where the portal and buildings would be constructed and mitigation of impacts was needed. There would also be a greater amount of excavated material to be removed and handled and a new shaft would be constructed in Castle Bromwich. This is why the Secretaries of State did not suggest in their decision letter that the BTE and BTEP fell outside s.20(2)(a) and concentrated instead on s.20(2)(c).[117]So what did the Secretaries of State mean in their decision letter by the test “new or different significant effects”? The only answer is to be found in the submissions for the respondents which say that they were referring to changes in the scheme which would not give rise to likely significant environmental effects greater (or more harmful) than those assessed in the EIA process for the Bill (see the respondents’ skeleton paras. 78-81 and 90 and the judgment in the High Court at [48]-[51] and [53]-[54]). They purported to base this approach on Milne. The respondents also describe the amended works as falling within the “environmental envelope” previously assessed for the Bill.[118]The question is whether that legal approach accords with s.20(2)(c) of the 2017 Act as a provision intended to ensure compliance with the objectives and requirements of the EIA Directive? In their written and oral submissions the respondents emphasised the words “covered by” an EIA in connection with the Bill. But that simply begs the question what is meant by “covered by”.[119]Fortunately, the 2017 Act supplies the answer in s.68(4) and (5). A development is excluded by s.20(2)(c) from the deemed planning permission in s.20(1) if a “deposited statement” did not contain informationin relation to that development which, at the time that document was deposited or published, constituted an “environmental statement” within the meaning of the 2011 EIA Regulations. Section 68(5) then goes on to define precisely those documents which qualify as a “deposited statement”.[120]In PACCAR Lord Sales said at [49]:
“The fact that Parliament provides a statutory definition of a term means that it is not satisfied that the term itself is sufficiently clear on its own. Where Parliament has taken the trouble to provide a definition, it is the words of the definition which are the primary guide to the meaning of the term defined. The weaker the inherent or established meaning of the term defined, the weaker must be its ability to throw light on Parliament’s meaning when setting out the express words of the definition which falls to be construed.”
Sometimes the term being defined has a “potency” that can colour the meaning of the words used in a definition section. But that is unlikely where there is no general consensus as to the core meaning or the limits of the term (see PACCAR at [48]-[49]). Here, the meaning of the phrase covered by an environmental assessment in connection with the Bill, particularly the words “covered by”, is uncertain. Evidently Parliament thought that the phrase needed to be defined in explicit and precise terms.[121]For development which is non-scheduled work to be “covered by” the environmental assessment for the Bill, HS2L must have produced at that stage information about that development sufficient for an ES. Schedule 4 of the 2011 EIA Regulations listed the material which would have been required during the Bill process, such as:• A description of the physical characteristics of the development and its land-use requirements during construction and operation, or at least the site, design and size of the development;• A description of the aspects of the environment likely to be significantly affected by the development and its likely significant effects on the environment;• A description of the mitigation and compensation measures to address likely significant adverse environmental effects.[122]Furthermore, s.68(4) proceeds on the basis that works assessed in the ES for the Bill have then been subject to the process of EIA in accordance with the Parliamentary Standing Orders. That allowed for consultees and the public to be made aware of that material and to make representations thereon and for the “environmental information” as a whole to be taken into account in the decision whether to approve the project. The process of EIA, as explained for example in Finch, is necessary in order for the objectives and requirements of the EIA Directive to be satisfied. Accordingly, s.20(2) was included in the statute so that non-scheduled development which falls within sub-paras. (a) and (c) will require an express grant of planning permission (“a development consent”) and EIA (unless exempt from that regime). The requirement for planning permission to be obtained enables appropriate conditions to be imposed on that consent, relating inter alia to any necessary mitigation for those altered works. This reading of the statute accords with the principles in Arts.2(1) and 4(2) and para.13(a) of Annex II to the EIA Directive (see [41] above).[123]If development which is non-scheduled work falls within s.20(2)(a) because it would be likely to have significant environmental effects, s.20(2)(c) read with s.68(4) and (5) ensures that the deemed planning permission granted by the 2017 Act only applies if that development was the subject of EIA during the Bill process. The test in s.20(2)(c) is not whether, if EIA were now to be carried out, the likely significant adverse environmental effects of that development would be no greater than, or no more harmful than, those assessed in the EIA for the Bill process for a different development of the same section of the project. The approach adopted by the Secretaries of State does not accord with s.20(c) read with s.68(4). It elides sup-paras. (a) and (c) of s.20(2). Instead it is necessary to identify the non-scheduled work amounting to “development” and to apply the tests in each of sub-paras, (a), (b) and (c) separately to that same development.[124]The respondents submit that this construction of s.20(2)(c) and s.68(4) and (5) would have absurd or unreasonable consequences. For example, if it were to be proposed that a scheduled work such as a tunnel were to be extended by 10m or some longer but still modest distance, HS2L would not be able to rely upon the deemed planning permission and would need to apply for a fresh consent. That is not so. The deemed planning permission in s.20(1) is only disapplied by sub-section (2) if the non-scheduled work falls within all three sub-paragraphs (a) to (c). Those provisions are cumulative. So, if a modest extension of a tunnel would not itself be likely to have significant environmental effects, it would fall outside sub-para. (a) and HS2L would be able to rely upon the permission conferred by s.20(1), without needing to address s.20(2)(b) and (c). This straightforward example stands in marked contrast to an alteration of the scheduled works of the nature and scale of the BTE. Not surprisingly, the Secretaries of State did not suggest in their decision letter that those works would themselves be unlikely to have significant environmental effects.[125]By definition, a non-scheduled work will not have been described in sched.1 to the 2017 Act. In some instances a non-scheduled work may be in substitution for scheduled work, but in many instances it will not. Either way, the ES for the Bill may have provided information sufficient to address significant environmental effects likely to arise from non-scheduled works. For example, an assessment may have been made of built development based on indicative drawings and material. But even if the environmental effects of a non-scheduled work were not assessed in the ES, the deemed planning permission in s.20(1) will nevertheless apply if the decision-maker judges that those effects would not be likely to be significant (s.20(2)(a)). On the other hand, if the non-scheduled work would be likely to have significant environmental effects which were not assessed in the ES for the Bill, there is no reason why, applying the objectives and requirements of the EIA Directive, an express grant of planning permission and EIA should not be required. Similarly, there is no reason why the same should not also apply where such non-scheduled work is to be carried out in place of scheduled work.[126]For the above reasons the Secretaries of State erred in DL 11 when they rejected the approach taken by the Inspector to s.20(2) on this basis:
“The Secretaries of State do not agree that sub-section (2)(c) should be construed as excluding any development which differs from the detailed description set out in the ES which was placed before Parliament.”
(emphasis added) Section 20(2) has to be read as a whole and in context. If the non-scheduled works would not be likely to have significant environmental effects, the deemed planning permission in s.20(1) will apply. The proper construction of s.20(2) does not exclude from s 20(1) any development which differs from the detailed description set out in the ES for the Bill.[127]I readily acknowledge that in some cases where EIA for a non-scheduled work is carried out the decision-maker may conclude that, although the likely significant environmental effects of a non-scheduled work differ from those previously assessed in the ES and environmental assessment for the Bill, taken overall they are no greater or more harmful than those effects, which by definition Parliament has accepted. But in such a case the requirement to obtain planning permission and to carry out EIA should not ordinarily be a long drawn-out process. Certainly, it should not take the period of nearly 2 years 8 months which elapsed between the making of the sched.17 application and the decision letter in this case. As this court has made clear, Parliament’s scheme in sched.17 was premised upon duties of mutual co-operation between HS2L and local planning authorities, because of the public interest in a nationally important infrastructure project (Hillingdon at [76]-[77] and [80]). That same public interest also requires that a planning application for non-scheduled works and EIA be handled efficiently by all concerned.[128]HS2L has not produced any evidence in support of the suggestion that the construction of s.20(2)(c) which I consider to be correct would lead to unreasonable consequences. In any event, it is necessary to have in mind the following passage from the judgment of Lord Sales in PACCAR at [43]:
“I would add that the courts have to be careful to ensure that they do not rely on the presumption against absurdity in order to substitute their view of what is reasonable for the policy chosen by the legislature, which may be reasonable in its own estimation. The constitutional position that legislative choice is for Parliament cannot be undermined under the guise of the presumption against absurdity.”
[129]There is also the other side of the coin. On their interpretation of the 2017 Act, so long as it is judged that the environmental effects of non-scheduled works are no greater than those assessed in the EIA for the Bill in relation to the same part of Phase One, the planning consent in s 20(1) is not disapplied by s.20(2)(c) and no further EIA is required, no matter how different in nature, scale or location those individual effects comprised in the overall assessment of impact may be. That interpretation does not accord with the language of s.20(2)(c) and s.68(4). Nor does it accord with Arts.2(1) and 4(2) and para.13(a) of Annex to the EIA Directive, which, in the light of the Buckinghamshire case, the draftsman of the 2017 Act would have had well in mind. In effect, the respondents’ interpretation allows the requirement for development consent and EIA to be avoided by the decision-maker comparing the environmental effects of that which has already been approved following EIA during the Bill process with the environmental effects of different works which have not been subject to EIA, including consultation with public bodies, representations by the public and the measures for mitigating those effects.[130]Suppose a detailed planning permission is granted for a large office park following compliance with EIA legislation, but that development is not carried out. Subsequently the developer seeks planning permission for a storage and distribution scheme on the same site which itself would be likely to have significant but different environmental effects. No one would suggest that a requirement for EIA in relation to that second scheme could be avoided by the developer comparing the environmental effects of the two schemes to show that the overall effects of the latter were no greater or no more harmful than those of the former. The environmental effects of two projects may differ in nature and degree and some may be adverse effects whereas others may be beneficial. Measures for mitigating those effects and their efficacy may differ. Comparing the overall environmental effects of two schemes will therefore often involve striking a balance in each case between competing factors and/or factors of different degrees of significance. Such a comparison by a developer, even if accepted by the decision-maker, does not overcome or satisfy the legislative requirement for EIA to be carried out on the second scheme. Instead, the outcome of EIA on the second scheme, compared to the EIA on the first, may be taken into account in deciding whether a development consent should be granted for the second scheme, but that is a different matter.[131]However, the respondents say that the position is different where the principle in Milne applies and that that is what Parliament had in mind when enacting s.20(2)(c) and s.68(4) of the 2017 Act. This was the basis upon which the judge rejected ground 2 of the challenge. But what did Milne decide?[132]It is necessary to see Milne in the context of the first of the two decisions of Sullivan J on the interaction of outline planning permissions and the EIA regime in relation to the development of the same site (R v Rochdale Metropolitan Borough Council ex parte Tew [2000] Env. L.R. 1). In Tew a developer obtained a “bare” outline planning permission for the development of a site of 213ha as a business park. All “reserved matters” were to be the subject of subsequent approvals over a period of 10 years. The High Court quashed the permission on the ground that there had been a breach of the relevant EIA legislation. That required the developer to provide inter alia a description of the project, including its site, design and size. But the application had only been accompanied by an indicative schedule of land uses and floorspace figures and a masterplan solely for illustrative purposes. The ES assessed the likely environmental effects of the illustrative proposals, but those proposals were not incorporated in the grant of planning permission. They did not define the development authorised to be constructed. Indeed, a condition stated that the masterplan was not approved because it had given insufficient information. Accordingly, a further condition required the submission and approval of a Framework Document showing the design, layout and phasing of the different parts of the scheme (p.22).[133]The Court rejected the LPA’s submission (at p.26) that it had imposed conditions to ensure that the environmental impact of the details of the reserved matters would not be significantly different from that assessed in the ES. Sullivan J held that although Annexes I and II used generalised descriptions to bring projects within the ambit of the EIA Directive, the Directive required an adequate “description” of the development and its characteristics so that the assessment of its likely significant environmental effects, including the consideration of mitigation measures, required by art. 5 and Annex IV could be carried out (pp. 27 and 30). Here the application for planning permission did not contain any information as to the design, size or scale of the development to be authorised. The fundamental problem was that the ES assessed the environmental effects of a development described by the illustrative masterplan and schedule of uses and areas, but the outline permission was not tied in any way to the description” of the development in those documents, for example, in the grant of permission and/or by conditions (p.30). The development in the masterplan and schedule was not the development for which permission was granted (p.31).[134]The developer made a further application for outline planning permission which came before Sullivan J in Milne. This application incorporated a schedule of development, a development framework and a masterplan into the application for which permission was sought. Conditions of the permission required the development to be carried out in substantial compliance with the development framework, masterplan and building layouts. Building heights were controlled by reference to the figures specified in the schedule of development. Conditions also required the development to be carried out in accordance with the principles in the development framework (including phasing) and the mitigation measures shown in the ES ([19]-[31]).The claimant submitted that, as matter of law, no outline planning permission could be granted for a development which required EIA, alternatively that the “description” of the proposed development in this case was legally insufficient to comply with EIA legislation [41]. Sullivan J rejected both arguments.[135]Sullivan J held that the legal requirement to provide a “description” of a project, including its site, design and size, is sufficiently flexible to cater for the nature of that project. For example, the design of a business park is often not fixed at the outset by its very nature. It may evolve over a number of years in response to market demand. It is for the decision-maker to judge whether the proposed degree of flexibility for a project is acceptable and whether the developer has provided sufficient information on its likely environmental effects ([89]-[90] and [95]). Provided that(1) the outline application has acknowledged the need for details of the project to evolve within clearly defined parameters,(2) the ES has taken into account that need and those parameters and assessed the likely significant effects of such a flexible project and(3) the outline planning permission imposes conditions to ensure that the process of evolution keeps within the parameters applied for and assessed, the project, as it evolves with the benefit of approvals of reserved matters, remains the same as the project which was assessed [93].[136]The information required by the EIA Directive to be included in relation to the “description” of the development proposed must be sufficient to enable the likely significant effects to be assessed and the mitigation measures to be described in accordance with Annex IV [104]. In addition, the development described and assessed in the ES must be the development which is authorised by the development consent [105].[137]At [47] of his judgment in the present case the judge relied upon [126]-[128] of Milne. It is necessary to read those paragraphs in the context of [123] and [125] where Sullivan J had cited this passage from his judgment in Tew at p.29:
“If consideration of some of the environmental impacts and mitigation measures is effectively postponed until the reserved matters stage, the decision to grant planning permission would have been taken with only a partial rather than a "full knowledge" of the likely significant effects of the project. That is not to suggest that full knowledge requires an environmental statement to contain every conceivable scrap of environmental information about a particular project. The directive and the Assessment Regulations require likely significant effects to be assessed. It will be for the local planning authority to decide whether a particular effect is significant, but a decision to defer a description of a likely significant adverse effect and any measures to avoid, reduce or remedy it, to a later stage would not be in accordance with the terms of Sched. 3, would conflict with the public's right to make an input into the environmental information and would, therefore, conflict with the underlying purpose of the directive.”
[138]At [126] Sullivan J accepted that the LPA’s grant of consent in the circumstances of that case had not involved deferring a decision to the reserved matters stage on anything which was likely to have a significant environmental effect, or any mitigation measures in respect of such an effect. In part that involved a legal assumption that the controls at reserved matters stage would be operated with reasonable competence so as not to give rise to additional significant environmental effects ([127]-[128]). All that Sullivan J was saying was that an EIA and outline planning permission which satisfied the principles he had previously laid down (see [135]-[136] above) would not conflict with the principles he had set out in Tew in the passage cited in [137] above.[139]The test laid down in s.68(4) of the 2017 Act is whether there was information in a deposited statement in relation to “the development”, that is the non-scheduled work, which, at the time that document was deposited or published, constituted an ES under the 2011 EIA Regulations. The 2017 Act then assumes that the EIA process laid down by Parliamentary Standing Orders was followed. The essential point is that the test for determining whether information qualifies under s.68(4) incorporates the requirements for an ES, referred to in [43] and [46] above. Thus, an ES must contain an adequate “description” of the project, its likely significant environmental effects and the mitigation measures to address those effects. Each of those requirements is specifically related to the development in question, as described in the ES.[140]Tew and Milne simply examined how an outline planning permission for a flexible form of development may satisfy those requirements of EIA legislation. The principles laid down in those decisions depend upon two key concepts which are interlinked: compliance with the components of the EIA process and a description of the project assessed by EIA and authorised by the development consent. An outline planning permission may be granted for a project of a flexible nature, but the nature and degree of the flexibility sought by the applicant must be capable of being, and actually be, assessed in the EIA process before an outline consent is granted and the scope of that project must be limited to that description of the project and its environmental effects and mitigation. In terms of the EIA Directive, the process is important because it provides for consultation and public participation in decision-making, the gathering of “environmental information” going beyond that contained in the ES prepared by the developer, mitigation measures and improving the quality of the decision on whether or not to grant a consent.[141]Practitioners often use the phrases “environmental envelope” or “Rochdale envelope” as shorthand for the principles in Tew and Milne. But as Mr James Strachan KC rightly pointed out, that language does not appear in the judgments of Sullivan J. The use of this shorthand is acceptable so long as it does not conflict with or undermine the principles set out in [133], [135]-[136] and [138]-[140] above or with Art.2(1), Art.4(2) and para.13 of Annex II of the EIA Directive (or other equivalent provisions).[142]For all these reasons, Tew and Milne do not support the construction of s.20(2)(c) of the 2017 Act which the Secretaries of State adopted and the judge upheld. Instead, those decisions are consistent with the correct construction of s.20(2)(c) set out above (see [119] and [121]-[123]).[143]Furthermore, in the present case, the description of the relevant part of the project which was assessed in the ES in order to comply with the EIA Directive comprised scheduled works, namely a railway constructed on embankments and a viaduct. That description of the project (or development) did not include the BTE and its eastern portal. The Inspector recorded in IR 41 that it was common ground that the BTE had not been the subject of environmental assessment. Paragraphs 2.6.18 – 2.6.19 of Community Forum Area Report No.25 in Vol.2 of the ES stated that the BTE had not been included in the scheme and assessed because the scheduled works were “considered to offer the greatest environmental benefits in comparison to other options”. The BTE and eastern portal have not been subject to EIA compliant with Milne.[144]However, the correct interpretation of s.20(2)(c) should not be seen as a means by which those who still object to the Phase One project may improperly seek to impede or materially delay its execution. I say that for the following reasons:(1) The ES for the Bill may have provided sufficient information to assess the likely significant environmental effects of non-scheduled works, whether identified during the Bill process or after the passing of the 2017 Act;(2) Even where a proposed change to Phase One works is not covered by the environmental assessment in connection with the Bill (s.20(c)), the development will still have the benefit of the deemed planning consent if it would not be likely to have significant environmental effects (s.20(a)) or, even where it would, it is exempt from EIA (s.20(b);(3) HS2L can apply to a local planning authority for a screening opinion that the proposal does not constitute EIA development. If the authority should disagree, HS2L may apply to the Secretary of State for a screening direction;(4) Where an express grant of planning permission is necessary, it is a relevant planning consideration that Parliament has authorised Phase One through the 2017 Act as an infrastructure project of national importance. That also applies to development authorised by the Act which does not benefit from the deemed planning permission in s.20(1);(5) Because of that public interest, the planning control exercisable under the Act for development authorised by the planning permission in s.20 assumes duties of mutual co-operation between HS2L and local planning authorities and efficient handling of the approval process. That same public interest in procedural efficiency also applies to the handling of planning applications, and to any EIA that may be required, for development falling outside the scope of s.20;(6) A relevant consideration in the handling of such planning applications is the fact that Parliament has decided that the impacts of the works authorised by the Act are acceptable and the impacts addressed in the EIA for the Bill are acceptable;(7) Where a local planning authority is failing to handle the planning process efficiently and reasonably, HS2L can appeal against a deemed refusal to the Secretary of State. Alternatively, the Secretary of State can call in an application for his own determination;(8) The Planning Inspectorate is well able to programme the appeal process and any hearings efficiently.

Conclusion

[145]For the above reasons I conclude that in their decision letter dated 14 May 2024 the Secretaries of State misinterpreted s.20(2)(c) of the 2017 Act and that ground 2 of the appeal should be upheld. On a true construction, a development which is non-scheduled work falls within s.20(2)(c) if a “deposited statement” for the Bill did not contain informationin relation to that development which, at the time that document was deposited or published, constituted an “environmental statement” within the meaning of the 2011 EIA Regulations. The test in s.20(2)(c) is not whether, if EIA were now to be carried out, the likely significant adverse environmental effects of that development would be no greater than, or no more harmful than, those assessed in the ES for the Bill for a different development of the same part of the project.

LADY JUSTICE KING

[146]As I have already noted, NWBC does not ask for an order quashing that decision. Instead, the authority is entitled to a declaration in the following terms:
“A declaration that the deemed planning permission conferred by s.20(1) of the High Speed Rail (London-West Midlands) Act 2017 does not apply to the Bromwich Tunnel Extension and the tunnel’s eastern portal, referred to in the respondents’ decision letter dated 14 May 2024.”
[147]I agree with Holgate LJ and the Vice President that the appeal on Ground 2 should be allowed and that a declaration should be made in the terms proposed by Holgate LJ at [146].[148]I would also wish to endorse Holgate LJ’s observations at [144]. Allowing the appeal on Ground 2 cannot be “seen as a means by which those who still object to the Phase One project may improperly seek to impede or materially delay its execution” . Equally local planning authorities must recognise the importance of working with efficiency and at speed when considering such applications which are critical to the progress of this much delayed infrastructure project of national importance.

LORD JUSTICE BEAN, VICE-PRESIDENT OF THE COURT OF APPEAL, CIVIL DIVISION:

[149]On Ground 1 I agree with Holgate LJ, for the reasons which he gives, that the BTE was development authorised by s.2(1) of the 2017 Act and that Ground 1 therefore fails.[150]On Ground 2, I note that different views have been taken at different stages of the dispute. In March 2021 the advice of the Department of Transport was that the proposed changes involving the creation of the BTE and its portal in the area of Water Orton were likely to have significant effects on the environment even if those were no greater than the effects of the previous proposal, and that an EIA was therefore needed. The Inspector who reported exactly two years later took the same view. He also concluded that the changes to the scheme fell within s.20(2)(c). However, in their decision letter of 14 May 2024, the decision-makers, the Secretaries of State, took a different view on the construction of s.20(2)(c) and in his judgment of 20 May 2025 Dove J agreed with that construction.[151]By virtue of s.20(1) of the 2017 Act, since the BTE was development authorized by the Act, it was deemed to have planning permission unless each of the three subparagraphs of s.20(2) applied. One of these – subparagraph (b) - is that the BTE was not exempt development. It is agreed that it was not, and therefore no more need be said about (b).[152]The next subparagraph to be considered is s.20(2)(c). This involves asking whether the BTE was “covered by” an environmental assessment in connection with the Bill for the 2017 Act. But s.20(2)(c) has to be read in conjunction with the provision in the interpretation section of the Act, s.68, subsection (4) of which provides that development is “covered by an environment assessment in connection with the Bill if it is development in relation to which information contained in a deposited statement”, deposited during the long parliamentary passage of the Bill, constituted, at the time of the statement’s deposit or publication, an environmental statement within the meaning of the EIA Regulations.[153]I do not see how it can be said that the BTE and its portal were “contained in” or “covered by” the statements deposited during the Parliamentary process. Plainly the amended scheme was not considered by Parliament.[154]The critical question is therefore the application of s.20(2)(a) of the Act. There is no deemed planning permission if the proposed development is “likely to have significant effects on the environment by virtue of factors such as its nature, size or location”. As Holgate LJ emphasises, any likely effects which would not be significant do not negative the planning permission deemed by s.20(1) to have been given.[155]Viewing the changes from, say, a regional perspective it might be thought that the overall effects on the environment of the proposed BTE and portal are less than those of the original scheme for the area, which included, for example, a viaduct. But from the local perspective of residents in the Water Orton area, the BTE is likely to have significant effects on the environment. I therefore agree with Holgate LJ that the original view of the Department of Transport in its screening opinion, based on the assessment in the Screening Report of HS2L, was the correct one.[156]For these reasons and those given by Holgate LJ, with which I entirely agree, I too would allow the Council’s appeal on Ground 2 and grant the declaration which Holgate LJ proposes.