Trudie Elizabeth James, R (on the application of) v London Borough of Enfield [2026] EWHC 1811 (Admin)

[2026] EWHC 1811 (Admin)Case No AC-2026-LON-001113
IN THE HIGH COURT OF JUSTICE
KING'S BENCH DIVISION
PLANNING COURT
Venue Royal Courts of Justice, Strand, London, WC2A 2LLDate 17/07/2026
Before
Timothy Corner KCSitting as a Deputy High Court Judge
Between
The King (on the application of Trudie Elizabeth James)ClaimantLondon Borough of EnfieldDefendantOleksandr Shtykhno (1)Anhelina Shtykhno (2)Interested Parties
The Claimant in person for in personGiles Atkinson (instructed by the solicitor to the London Borough of Enfield) for DefendantHarley Ronan (instructed by Khift Ltd) for first Interested Party. The Second Interested Party did not appear and was not represented.Hearing Hearing date: 25 June 2026
Approved JudgmentThis judgment was handed down remotely at 2pm on Friday 17 July 2026 by circulation to the parties or their representatives by e-mail and by release to the National Archives..............................

Timothy Corner KC:

[1]In this claim for judicial review, the claimant challenges the grant of planning permission (ref: 25/03926/HOU) (“the permission”) by the defendant (“the council”) to the Interested Parties (“the IPs”) on 5 February 2026 for: “Part single/part 2 Storey side and rear extensions, front porch and conversion of loft into habitable space” at 51 Lonsdale Drive, Enfield EN2 7LR (“no 51”).[2]The claimant is the immediate neighbour of no 51 and lives at 53 Lonsdale Drive (“no 53”). The claim is based on the loss of daylight to a kitchen window (W1) in the claimant’s house in respect of which it is claimed that the council has fallen into error in the grant of planning permission by: i) Making a mistake of fact: ii) Failing to discharge its Public Sector Equality Duty (“PSED”) under the Equality Act 2010 in respect of a resident at no 53. iii) Erroneously taking account of permitted development rights of no 51 as a fall-back position.[3]The claimant seeks the quashing of the permission. The hearing before me concerned whether the claimant should be granted permission to apply for judicial review and also the claimant’s claim for interim relief, in which the claimant seeks:
“1. Interim injunction: the Interested Party is restrained until the final determination of this claim or further Order of this Court from commencing or carrying out any development or construction works at [no 51], pursuant to [the permission].” 2. Stay of Permission: The operation of [the permission] is stayed with immediate effect pending the final determination of the Claimant’s application for Judicial Review.”
BACKGROUND

BACKGROUND

[4]An application for permission for the development (“the application”) was made to the council on 25 November 2025. The application was accompanied by a report (“the Rowland report”) entitled “Considerations on the potential impact on sunlight/daylight reaching the ground floor side window at no. 53 Lonsdale Drive” dated 8 December 2025 and prepared by the architect who had submitted the planning application, Elena Rowland.[5]The Rowland report notes that the claimant, on becoming aware of the application, removed the trellis from the top and reduced the height of a fence situated immediately outside window W1. Photographs showing the fence before and after its lowering are included in the Rowland report and the lowering is estimated to have taken place in early December 2025. The claimant said in an e-mail to the IPs that she did this to allow the IPs’ light study to take readings from the middle of the window.[6]The Rowland report concludes that the proposed extension at no 51 would have a negligible impact on the sunlight and daylight reaching window W1, partly because the window is north facing but also because it was considered that the kitchen would receive daylight through the existing conservatory to the rear of no 53.[7]A further document on the sunlight and daylight effects of the application, entitled Sunlight and Daylight Assessments Impact Assessment (“the impact assessment”) and dated 30 January 2026, was produced for the IPs by Sunlight Assessments UK and submitted to the council.[8]The impact assessment refers to the BRE Guide “Site layout planning for daylight and sunlight: a guide to good practice” published in 2022 (“the BRE guide”) as follows:
“1.3 The Local Authority will be informed of this by the [BRE guide].. This document is the principal guidance in this area and sets out the methodology for measuring light and recommends what it considers to be permitted or unobtrusive levels of change. 1.4 The BRE guidelines are not mandatory, though local planning authorities and planning inspectors will consider the suitability of a proposed scheme for a site within the context of BRE guidance. Consideration will be given to the urban context within which a scheme is located, and the daylight and sunlight will be one of several planning considerations which the local authority will weigh.”
[9]The impact assessment refers to the following summary in para 2.2.3 of the BRE guide (which I set out below) of the methodology for assessment of the impact of developments on the daylight received by nearby windows, including Vertical Sky Component (“VSC”).[10]The impact assessment assesses all windows likely or possibly to be affected by the development, including those which light the conservatories to the rear of no 53, as well as window W1.[11]Window W1 is assessed as having an existing VSC of 18.1% which would be reduced to 7.22% with the extension at no 51 built as proposed, retaining only 40% of its existing value. Taken in isolation, the daylight to window W1 because of the development would fall below the BRE guidance.[12]However, the weighted results for all the windows taken together (at appendix 3) shows that they would retain enough VSC for there to be an improvement overall, with the overall ratio of future to previous VSC being 100.1%.[13]Based on this analysis the impact assessment concludes as follows:
“8.1 The daylight and sunlight to the analysed windows and garden space of [no 53] will not experience a noticeable reduction of daylight and sunlight as set out in the BRE guidelines. 8.2 We, therefore, conclude that the effects of the proposed scheme in relation to daylight and sunlight are BRE compliant and we have identified no grounds for rejection of a planning application for this proposal.”
[14]The claimant submitted several objections to the application, including comments submitted on 23rd December 2025. Comments made on that date were accompanied by a “flyaround” animation of the inside of the claimant’s house designed to show how little sunlight would penetrate window W1. The claimant said:
“With the input of the supplied proposed application data into Home 3D software to help visualise the effect of the proposed application and using its ‘fly around’ simulator it clearly shows that the sun would never be able to shine directly through our kitchen window ever again and the only light from that would come directly from the sun to the window would not be through it but be when it was briefly glancing across it from the very thin corridor opening of 1418mm which extends for approximately 4.8m to the left of the centre of the window as you are looking out of the window and an extremely thin corridor of 4.32m to the right which is reduced to an even thinner corridor opening of 915mm. The proposed application if approved would ultimately make this window unfit for the purpose it has joyously provided for over 20 years and force us to permanently illuminate this end of the kitchen and dining area artificially to be able to function (because our building is 2 storey and we can't install roof daylight). The total loss of direct sunlight flowing through the window as it does now and devastating reduction in daylight through it would not only make the window unfit for purpose but also completely destroy all well being benefits to us particularly due to our state of health and be very stressful and depressing.”
[15]The claimant submitted a further objection, on 2 February 2026, after having seen the impact assessment. She did not suggest that the weighted average of window W1 was invalid because the kitchen and conservatories did not comprise one room, or that windows in the conservatories were more than 5m from window W1.[16]The application was delegated to the council’s planning officers to determine and was considered in a delegated report (“the officer report”).[17]The officer report stated that there had been one objection (this was from the claimant) and summarised the objection as follows:
“-Inaccurate information in the application -Loss of daylight/sunlight -Excessive bulk/overbearing impact -Incomplete or missing information on plans -Tree adjacent to site.”
[18]Under the heading “Daylight, and sunlight impacts”, the officer report reproduced existing and proposed site plans, proposed floor plan and proposed rear elevation, a view from inside the kitchen and dining area window at no 53 (W1) (before the white fence between window W1 and no 51 had been reduced in height and the wide holed trellis above the white fence removed) and a view from the same window from the outside after the reduction in height of the white fence and removal of the trellis.[19]The officer report continued:
“The proposal includes a two-storey side extension whose rear building line would project approximately 0.83m beyond the main rear elevation of No.53. The extension would sit well behind the rear wall of the neighbour’s existing conservatory. Given the modest depth of the projection, its relationship to the conservatory and the fact that the affected side-facing window at No.53 is orientated north-facing, the development would not give rise to any material loss of sunlight... It is also a material consideration that, under permitted development rights, the applicant could erect a side extension up to half the width of the original dwelling, potentially resulting in a structure closer to the shared boundary than is currently proposed.”
[20]Under the heading “Daylight to Neighbouring Room (No. 53)” the officer report stated:
“The submitted Daylight and Sunlight Assessment identifies one window Ground Floor W1, on the flank elevation of No. 53, serving the kitchen/living/dining/conservatory space, as being impacted by the proposal. The assessment reports that the Vertical Sky Component (VSC) at W1 would reduce from 18.10% to 7.22% retaining 40% of its former value, which is well below the BRE guideline threshold of 0.8 times former value for noticeable loss. Under BRE 2.2.7, such a reduction indicates a material loss of daylight to this individual window. However, W1 is one of a large number of windows serving the same open- plan room. The assessment provides VSC values for windows W2-W24 along the predominantly glazed rear/side elevation, all of which show very high VSC values and no losses as a result of the development. The assessment also presents a weighted-average VSC for the room which increases slightly, giving a ratio of 1.01, indicating that overall available skylight to the room’s glazing as a whole is not reduced. Although W1 experiences a marked reduction in VSC, the window is already tightly enclosed at the boundary by No. 53’s substantial 2-storey side extension and large rear conservatory, which replaced the property’s original kitchen window and reconfigured the internal layout. The window also sits very close to the boundary line and is further constrained by the boundary fence. As noted in BRE guidance (para. 2.2.3), consideration may be given to whether the affected building is itself a ‘good neighbour’, that is, whether its own configuration has already constrained available daylight. Given the dominant contribution of the extensive rear glazing (W2-W24) to the room’s daylighting, and the fact that none of these windows suffer any material loss as a result of the development, it is reasonable to conclude that the room as a whole is likely to continue to receive good levels of daylight from its primary orientation. This observation is supported by the weighted VSC analysis. On balance, and taking into account the existing built context at No. 53, the proposed extension at No. 51 is not considered to cause a demonstrably harmful loss of daylight or outlook to the neighbour sufficient to warrant refusal. The single failing window (W1) is not the primary source of daylight to the room, and the main rear glazing continues to achieve high VSC values with negligible loss overall. Additionally, the separation of approximately 1.4m between the proposed flank wall and W1 is not considered to create an undue sense of enclosure beyond that already arising from the proximity to No. 53’s own extensions to the shared boundary.”
[21]Under the heading “Reason for Recommendation: GRANTED” the officer report stated:
“Subject to the recommended conditions, and for the reasons considered above, whilst the Council recognises the merits of the proposal, these have been assessed against the policies of the development plan and other material planning considerations. Officers consider that on balance, the benefits of granting permission would significantly and demonstrably outweigh the adverse impacts, when assessed against the policies in the NPPF taken as a whole.”
[22]Under the heading “Public Sector Equalities Duty” the officer report stated:
“All other planning considerations including equalities and the Councils [sic] obligations to have due regard to the objectives of the Public Sector Equality Duty [Section 149 of the Equality Act 2010] have been duly considered, but none are considered sufficient to alter the recommendation.”
[23]After the permission for the development had been granted, the claimant commissioned and sent to the council a review of the Rowland report, the impact assessment and the officer report by BRE (“the BRE report”) dated 24 February 2026.[24]BRE's conclusions were apparently based on photographs and layout information showing the actual internal layout of the claimant’s property shown to BRE but which appears not to have been seen by either Elena Rowland, Sunlight Assessments UK (the author of the impact assessment) or the council officer preparing the delegated report. BRE did not conduct a site visit.[25]The BRE report says:
“Overall, the Sunlight Assessments UK report has performed an area weighted average of the W1 kitchen window and all of the conservatory glazing analysed and concludes that the result would meet the BRE guidelines. However, this has assumed that the kitchen and conservatory are a single open space room. You have provided us with photographs and layout information that show that although there are apertures from the kitchen to conservatory areas, they are not part of the same open plan space. This approach to the weighted average of results would therefore not be appropriate because: -the space is not a single open plan space, and even if it were: -the information you have provided us with suggests that at least some of the conservatory glazing would be more than 5m from window W1. The Sunlight Assessments UK report therefore does not appropriately perform the glazing weighted average results for the kitchen. Our understanding is that the kitchen is lit by W1, an aperture to the south west to the conservatory discussed above (but not connected as an open plan space) and glazed doors on the opposite wall of W1 to another conservatory area. W1 is the only external aperture and therefore a key source of daylight to the room. Since the other two apertures do receive some daylight via conservatory areas and the layout you have provided suggests they are all closer than 5m to each other, a glazing area weighted average could be used, but based on the glazing area to the kitchen, and not the conservatory. However, there are no established guidelines on whether, or how, to account for the reduced daylight reaching the two additional apertures, given that they receive light indirectly through the conservatories. The decision report repeats the same misunderstanding of the layout of the kitchen and conservatory area and states: ‘However, W1 is one of a large number of windows serving the same open-plan room. The assessment provides VSC values for windows W2-W24 [conservatory glazing] along the predominantly glazed rear/side elevation, all of which show very high VSC values and no losses as a result of the development.’ And later concludes: ‘Given the dominant contribution of the extensive rear glazing (W2–W24) to the room’s daylighting, and the fact that none of these windows suffer any material loss as a result of the development, it is reasonable to conclude that the room as a whole is likely to continue to receive good levels of daylight from its primary orientation. This observation is supported by the weighted VSC analysis.’ However, as described above the glazing weighted analysis has not been appropriately undertaken for the actual layout of the kitchen.”
[26]The facts about the layout of the claimant’s property appear to be these. The kitchen itself has one external window, W1. It is separated from the conservatory immediately to its rear by the rear wall of the kitchen, in which there is a window. It is separated from the conservatory to the rear of the lounge by sliding doors. Based on the layout she produced showing the planning history of her two properties from 1973-2000, the claimant asserted that some of the windows in the two conservatories relied on in the impact assessment are more than 5m from window W1, but the evidence before me did not clarify this point. LEGAL FRAMEWORK[27]The principles governing mistake of fact in the planning context are set out in E vSecretary of State for the Home Department[2004] EWCA Civ 49 (“E v SSHD”); [2004] Q.B. 1044as applied in R. (on the application of Watt) v Hackney LBC [2016] EWHC 1978 (Admin); [2017] J.P.L. 192). These are that there are four ordinary requirements for such a challenge to succeed. First, there must have been a mistake as to an existing fact, including a mistake as to the availability of evidence on a particular matter. Secondly, the fact or evidence must have been “established”, in the sense that it was uncontentious and objectively verifiable. Thirdly, the appellant must not have been responsible for the mistake. Fourthly, the mistake must have played a material (not necessarily decisive) part in the decision-maker’s reasoning.[28]R (Newsmith Stainless Ltd) v Secretary of State for Transport and the Regions [2001] EWHC 74, [2017] PTSR 1126 contains guidance on establishing irrationality in planning decisions:
“[6] In any case, where an expert tribunal is the fact-finding body the threshold of Wednesbury unreasonableness is a difficult obstacle for an applicant to surmount. That difficulty is greatly increased in most planning cases because the inspector is not simply deciding questions of fact, he or she is reaching a series of planning judgments. For example: is a building in keeping with its surroundings? Could its impact on the landscape be sufficiently ameliorated by landscaping? Is the site sufficiently accessible by public transport etc? Since a significant element of judgment is involved there will usually be scope for a fairly broad range of possible views, none of which can be categorised as unreasonable. [7] Moreover, the inspector’s conclusions will invariably be based not merely upon the evidence heard at an inquiry or an informal hearing, or contained in written representations but, and this will often be of crucial importance, upon the impressions received on the site inspection. Against this background an applicant alleging an inspector has reached a Wednesbury unreasonable conclusion on matters of planning judgment faces a particularly daunting task. It might be thought that the basic principles set out above are so well known that they do not need restating. But the claimant’s challenge in the present case, although couched in terms of Wednesbury unreasonableness, is, in truth, a frontal assault upon the inspector’s conclusions on the planning merits of this Green Belt case.”
[29]In Barker Mill Estates Trustees v Test Valley BC [2017] J.P.L. 417, this court stressed that:
“[24]. A complaint of irrationality does not give a claimant an opportunity to revisit the planning merits of his appeal or of the Inspector's decision. ‘The Court must be astute to ensure that such challenges are not used as a cloak for a rerun of the arguments on the planning merits’ (Newsmith v Secretary of State for Environment, Transport and the Regions [2001] EWHC (Admin) 74 at paragraph 6). In any case where an expert tribunal such as a planning Inspector is the fact-finding body, the threshold for Wednesbury unreasonableness is a high and difficult hurdle for a claimant to surmount. This is greatly increased in most planning cases because the Inspector is not simply determining questions of fact, but is also concerned with making a planning judgment or a series of planning judgments. Because a substantial degree of judgment is involved, there will usually be scope for a fairly broad range of possible views by different decision-makers presented with the same materials, none of which could be categorised as unreasonable in the Wednesbury sense (Newsmith at paragraph 7). Against this background, a Claimant alleging that an Inspector has reached an irrational or perverse conclusion on matters of planning judgment ‘faces a particularly daunting task’ (Newsmith at paragraph 8).”
[30]Though Barker concerned an inspector’s decision, the principles apply also to decisions by local planning authorities.[31]The legal principles regarding PSED were helpfully summarised in Quarry Mews Ltd v Secretary of State for Housing Communities and Local Government and Oxford City Council [2025] EWHC 1968: “[11] …. It is accepted that the inspector was under such a duty so that in the course of his function, he must have regard to the need to(a) eliminate discrimination, harassment, victimisation and any other conduct that is prohibited by or under the 2010 Act;(b) advance equality of opportunity between persons who share a relevant protected characteristic and persons who do not share it;(c) foster good relations between persons who share a relevant protected characteristic and persons who do not share it. [12] The main principles were summarised in R (Bridges) v Chief Constable of South Wales Police [2020] 1 WLR 5037, in which reference was made to R (Bracking) v Secretary of State for Work and Pensions [2014] Eq LR 60, [25] approved by the Supreme Court in Hotak v Southwark London Borough Council [2015] UKSC 30 at [73] as follows: ‘(1) the PSED must be fulfilled before and at the time when a particular policy is being considered (2) the duty must be exercised in substance, with rigour and with an open mind. It is not a question of ticking boxes. (3) The duty is non delegable. (4) The duty is a continuing one. (5) If the relevant material is not available, there will be a duty to acquire it and this will frequently mean that some further consultation with appropriate groups is required. (6) Provided the court is satisfied that there has been a rigorous consideration of the duties, so that there is a proper appreciation of the potential impact of the decision on equality objectives and the desirability of promoting them, then it is for the decision maker to decide how much weight should be given to the various factors informing the decision...’ [13] The PSED requires a highly fact sensitive inquiry (R (Hough) v SSHD [2020] EWHC 1635…[106] and the rigorous consideration which requires the decision maker to have a proper appreciation of the potential impact of the decision on equality objectives and the desirability of promoting them….Steyn J in R (Devonshire Investments Ltd v Luton BC [2023] EWHC 978…. held that the PSED implies a duty of reasonable inquiry with a view to understanding the potential impact of a proposed decision on people with protected characteristics. She accepted at [55] that the nature of the function being exercised, and the context, may have an important impact on what is required to fulfil the duty of inquiry. How the duty is complied with is subject to challenge only on Wednesbury grounds. [14] In the context of planning decisions, Lindblom J ….in R (Coleman) v London Borough of Barnet [2012] EWHC 3725….when holding that a local planning authority had due regard to the PSED which had been fully set out in the planning officers report, said this: ‘66. As Dyson LJ said in [R (Baker) v Secretary of State for Communities and Local Government [2009] PTSR 809] (in paragraph 31), the duty is not a duty to achieve a result, but to have due regard to the need to achieve the statutory goals. This distinction, said Dyson LJ, is ‘vital’. The failure of a decision maker to make explicit reference to the relevant statutory provision would not determine whether the duty under statute had been performed, for this would be to sacrifice substance to form.’ [15] However, where it is found that a planning decision discloses that the PSED duty has not been complied with, the decision will be quashed...” ‘66. As Dyson LJ said in [R (Baker) v Secretary of State for Communities and Local Government [2009] PTSR 809] (in paragraph 31), the duty is not a duty to achieve a result, but to have due regard to the need to achieve the statutory goals. This distinction, said Dyson LJ, is ‘vital’. The failure of a decision maker to make explicit reference to the relevant statutory provision would not determine whether the duty under statute had been performed, for this would be to sacrifice substance to form.’[32]A planning decision-maker is not obliged to refer to every material consideration, however insignificant, and to deal with every argument, however peripheral: see e.g. Bolton Metropolitan Borough Council v Secretary of State for the Environment [2017] PTSR 1091 (1995).[33]It is well established, for example in South Buckinghamshire District Council v Secretary of State for the Environment, Transport and the Regions [1999] PCLR 72 and Snowden v Secretary of State for the Environment [1980] JPL 749 that for a “fall-back” development to be relevant to a planning decision, there must be a realistic prospect that the fall-back development will occur if the planning permission applied for is not granted.[34]When an application is made for interim relief, the court will consider whether there is a real issue to be tried – that is, whether there is a real as opposed to fanciful prospect that the claim will succeed at the substantive hearing – and whether the balance of convenience lies in favour of granting the interim order; see R (Medical Justice) v Secretary of State for the Home Department [2010] EWHC 1425 (Admin) at [6] – [13]. POLICY AND GUIDANCE[35]Enfield’s Development Management Document (“the DMD”), adopted in 2014, is part of the development plan for the area.[36]Policy DMD 8 is headed “General Standards for New Residential Development” and provides in part:
“1) New residential development will only permitted if all of the following relevant criteria are met. All development must:…….. c. Preserve amenity in terms of daylight, sunlight, outlook, privacy, overlooking, noise and disturbance….”
[37]Policy DMD 11 provides in part:
“Rear extensions 1.Proposed extensions will only be permitted if: a. There is no impact on the amenities of the original building and its neighbouring properties….”
[38]Policy DMD 14 governs side extensions but contains no provisions dealing specifically with the impact of extensions on neighbouring amenities.[39]Para 4.5.1 of the DMD says:
“Extensions to residential properties can be an efficient and, in difficult housing markets, more affordable and practical way of adapting to household changes. However, extensions may disrupt the established pattern and form of development and therefore may have impacts on residential amenity.”
[40]I have already mentioned the BRE guide. It is not part of the development plan. It was mentioned in the officer report as a Supplementary Planning Document (“SPD”). So far as I am aware, it is not an SPD in the sense of that term as set out in the Town and Country Planning (Local Planning) (England) Regulations 2012. However, it was common ground before me that the council relies on it when determining planning applications, and that the officer report did so in this case.[41]The BRE guide states:
“1.6…. The advice given here is not mandatory and the guide should not be seen as an instrument of planning policy; its aim is to help rather than constrain the designer. Although it gives numerical guidelines, these should be interpreted flexibly since natural lighting is only one of the many factors in site layout design... In special circumstances the developer or planning authority may wish to use different target values….. 2.2.8 If there would be a significant loss of light to the main window but the room also has one or more smaller windows, an overall VSC may be derived by weighting each VSC element in accordance with the proportion of the total glazing area represented by its window. For example, a room has a main window of area 2 m2 whose VSC would drop from 24% to 18%, 0 .75 times the value before. However, it also has a smaller window, area 1m2, for which the VSC would be unchanged at 30%. The area weighted VSC ‘before’ would be (24x2+30)/3=26%. ‘After’ it would be (18x2+30)/3=22%, 0.85 times the value ‘before’. Thus, loss of VSC to the room as a whole would meet the guideline. This method would only be appropriate in situations where the windows light the same areas of the room. It should not be used in situations such as a through lounge more than 5m from window to window, where, for example, a loss of light the front windows and front portion of the room may not be mitigated by daylight from the rear windows….. 2.2.23 If any part of a new building or extension, measured in a vertical section perpendicular to a main window wall of an existing building, from the centre of the lowest window, subtends an angle of more than 25° to the horizontal, then the diffuse day lighting of the existing building may be adversely affected. This will be the case if either: -The VSC measured at the centre of an existing main window is less than 27% and less than 0.80 times its former value -The area of the working plane in a room which can receive direct skylight is reduced to less than 0.80 times its former value.”
THE PARTIES’ SUBMISSIONS The claimant THE PARTIES’ SUBMISSIONS

The claimant

[42]The claimant’s case as set out in her Statement of Facts and Grounds challenges the grant of permission on the grounds of mistake of fact, irrationality and failure to take account of the equality/health considerations relevant to a resident of the claimant’s property.[43]For the purposes of the hearing before me, the claimant submitted a skeleton argument containing 50 pages. This skeleton contravened the rule in CPR 54A at para 12 that skeleton arguments must not contain more than 25 pages without the permission of the court.[44]Also, the claimant’s skeleton argument went much further than the grounds pleaded in the Statement of Facts and Grounds, making the following points: i) The council’s decision was irrational because of failure to perform its duty under Secretary of State for Education and Science v Tameside Metropolitan Borough Council [1977] AC 1014 to take reasonable steps to acquaint itself with the relevant information to determine the planning application (several references in the skeleton). ii) In uploading the impact assessment only 72 hours before planning permission was granted, the council behaved in a procedurally unfair way (skeleton p17). iii) The council’s decision was vitiated by predetermination and bias (skeleton p 4) as exemplified by the comment in its pre-application letter of 29 August 2025 that “no concerns are raised with regards to the loss of sunlight/daylight/outlook” (skeleton p 31-2). iv) The council’s decision was vitiated by its acceptance of the Rowland report, which contained important errors (skeleton p 12-13, p 27-30, 33-4) and allowing that report to be absent from the public register for 39 days was procedurally unfair (skeleton p 14-15). v) The council’s decision violated the rights of the claimant’s household under art. 8 of the European Convention (skeleton p 39). vi) The council’s decision did not provide adequate reasons (skeleton p 43).[45]Before the hearing, the claimant made no application pursuant to CPR 23 to amend her grounds to include the above points. At the hearing she did so, but then withdrew the application save for the addition of a new ground alleging that the council unlawfully took account of permitted development rights of no 51 as a fall-back position. The council and IP1 agreed to proceed on the basis of the claimant’s grounds as stated in her Statement of Facts and Grounds with the addition of the ground relating to permitted development rights.[46]The claimant’s main complaint is that the exercise contained in the impact assessment taking a weighted average of window W1 and the windows in the conservatories was invalid and contrary to the guidance in the BRE guide at para 2.2.8, for two reasons: i) The windows in the conservatories were not part of the same room as the kitchen; ii) At least some of the conservatory windows are more than 5m from window W1.[47]The claimant says the decision to grant permission was therefore vitiated by a mistake of fact. Further or alternatively the decision was irrational, because it was unreasonable to grant permission based on such an error. The claimant says (skeleton p 25) that the council could have found out about the wall between the kitchen and rear conservatory if it had checked its planning register, in particular two planning permissions, TP/73/0082 and TP/00/0958.[48]The claimant says that as a consequence of the irrational decision the council failed to apply section 38 (6) of the Planning and Compulsory Purchase Act 2004 (“the 2004 Act”) in relation to policies DMD 8 and 11 of the DMD.[49]The claimant also contends that in failing to take account of the health condition of a resident of the claimant’s property, the council failed to comply with its PSED under section 149 of the Equality Act 2010 to have regard to the need to advance equality of opportunity and eliminate discrimination in respect of individuals with protected characteristics. This is on the basis that the resident concerned – Mr Paul Davis – has a protected characteristic, namely disability and is Clinically Extremely Vulnerable (“CEV”).[50]The claimant also contends that the decision to grant planning permission was vitiated by the reliance on permitted development rights in the officer report. Permitted development rights should not be taken into account in the absence of evidence of a realistic possibility that they will be exercised.[51]As to interim relief, the claimant says she has a strong case, and that the balance of convenience favours the grant of the interim injunction sought. The claimant says the adverse impact on the health of the occupiers favours the injunction. This appears to be twofold: the effect of the loss of daylight on the ability to administer medication to the disabled resident and on wellbeing. The claimant also contends that implementation would cause “irreparable” harm. The council and IP1[52]The council contends that regardless of whether the kitchen/dining area served directly by W1 can accurately be described as “open plan”, that area is also lit from the two other “apertures” as BRE calls them: the window in the rear wall looking into the conservatory to the rear of the kitchen and the glazed sliding doors leading to the conservatory to the rear of the lounge.[53]The light to both conservatories, from which ultimately the kitchen area is lit via the apertures, is not affected by the proposed development at all.[54]This means that the council’s conclusions that on balance the proposed development would not cause a demonstrably harmful loss of daylight or outlook to the neighbour sufficient to warrant refusal are sound, because the single failing window (W1) is not the primary source of daylight to the room and the main rear glazing continues to achieve high VSC values. The characterisation of the area served by W1 as open plan in the officer report was not therefore a material error of fact.[55]IP1 submits that the dominant window to the kitchen is the large window in the rear wall, which appears from the plans submitted by the claimant with her skeleton to be in the region of seven feet wide. The essential point made in the officer report was not that the impact was acceptable because the room was open plan, but that there were other and more important sources of light to the kitchen apart from window W1, namely the conservatory to the rear of the kitchen and the conservatory to the rear of the lounge.[56]With reference to the first and second of the tests in E v SSHD, in the absence of any definition of “open plan”, it cannot straightforwardly be said that the area served by window W1 is or is not factually open plan, nor that this fact is uncontentious or objectively verifiable. What is open plan remains essentially a judgment, not something amenable to factual determination.[57]If, contrary to the above, the court finds that the area is not open plan, it remains the case that the third testin E v SSHD is not met; the claimant was at least partly responsible for the mistake by circulating the “flyaround” images which showed the area lit by W1 as not having any internal walls at all.[58]The grant of planning permission was therefore not vitiated by mistake of fact. The criticisms made of the methodology relied on by the council to reach its conclusion are inadmissible because the BRE report was not submitted before permission was granted, but they do not serve to vitiate the decision in any case. This is because, as acknowledged in the BRE report itself, the area lit by W1 (however it is described) is additionally lit by the window in the rear wall of the kitchen and the glazed sliding doors which lead to the conservatory behind the lounge. The light to both conservatories is not affected by the proposed development at all.[59]The council and IP1 further submit that there is no evidence that the officer who prepared the delegated report failed to consider the equality/health of the claimant and her household. The officer report refers to one letter of objection which summarises the claimant’s concerns briefly but accurately, and to the public consultation that has taken place. The claimant’s responses to the public consultation include specific notice to the council that a resident of no 53 is CEV on 23rd December 2025, and, on 18th January 2026, a so-called “Medical Warning” letter notifying the council that one of the residents of no 53 – Mr Davis – was a double stroke survivor and suffers severe neurological problems.[60]Equality is specifically referred to in the officer report in the section confirming that the objectives of the PSED under section 149 of the Equality Act have been duly considered but none of these is considered sufficient to alter the recommendation. Disability is a relevant protected characteristic.[61]The author of the officer report must be taken to have considered the health of the claimant and Mr Davis.[62]IP1 adds that the council was not obliged to take account of the personal circumstances of the occupiers of no 53.[63]As to permitted development rights, the council, supported by IP1, submits that it is obvious that there is a realistic possibility of the owner of no 51 implementing the permitted development rights.[64]IP1 adds that even if there was an error in the treatment of daylight to window W1, I must consider under section 31 (3C) of the Senior Courts Act 1981 whether the outcome for the claimant would have been substantially different had the conduct complained of not occurred. The outcome would not have been substantially different, because the light entering the kitchen via the conservatories is not materially affected by the development and it was that absence of impact on other sources of light to the kitchen that the officer report placed weight on, not the fact that the room was considered to be open plan. Further, the error (if there was an error) had no impact on any of the other matters which fed into the officer’s planning judgement.[65]As to interim relief, the council and IP1 say there is no serious issue to be tried because the claim is unarguable. In any case, the balance of convenience lies in favour of refusing interim relief.[66]The factors militating against the grant of an injunction include: i) A potentially significant delay to implementing the development pending the determination of the claim. That has the potential to manifest itself in the form of inability due to increased costs, and also delaying for the IPs the amenity value that the development will afford No. 51. ii) The public interest. The starting point is that the council has lawfully granted planning permission. In accordance with its statutory duties, it has decided that the development is in accordance with the local plan adopted by the democratically elected members of the council. Unless and until the court orders otherwise, the court should place considerable weight on that decision being respected and the IPs, as members of the public, being able to rely upon it.[67]The claimant’s assertions about the effect of the loss of light on the ability to administer medication to Mr Davis and the loss of daylight on wellbeing are refuted.[68]As to the first, there is no evidential basis for the assertion that the completion of the development would “render the kitchen unsafe for the resident’s medical care and recovery from strokes”, let alone that the steps taken to construct the development would have that effect. In various comments the claimant appears to accept that medication can still be administered with artificial light.[69]As to the second, there is no medical evidence before the court to support the allegation that implementing the development “would be detrimental to the health of the [CEV] resident I care for”. Even if there were, the claimant’s position overlooks: i) the undisputed factual position that, beyond W1, the development will not have a material impact on the conservatory; ii) that there is no question of any impact on any other part of the house suffering a loss of daylight; and iii) the amount of daylight in the kitchen will be increased by the development.[70]Therefore, even ifthe court entertains the assertion that the loss of light to W1 is a “medical necessity”, and even if the court puts to one side that there is no material loss of daylight to the kitchen, the rest of the house is entirely unaffected. The occupiers can avoid any harmful impact by simply using different rooms.[71]Finally, the claimant says that the commencement of development would cause “irreparable harm”. That is not correct. If the development were partly or wholly built out, and the planning permission is quashed, the development can be removed, and the site put back to exactly how it is at present. This is not a case involving the irredeemable loss of, e.g., a heritage asset. If the permission was wrongly granted, matters will be put back to as they are.[72]The claimant’s arguments therefore do not outweigh the potential negative impacts on the IPs, and the strong public interest in respecting the permission. The balance of convenience lies firmly against granting the injunction. DISCUSSION Mistake of fact[73]The officer report proceeded on the basis that though window W1 was substantially affected by the development, W1:
“is one of a large number of windows serving the same ‘open-plan’ room. The assessment provides VSC values for windows W2-W24 along the predominantly glazed rear/side elevation, all of which show very high VSC values and no losses as a result of the development. The assessment also presents a weighted-average VSC for the room which increases slightly, giving a ratio of 1.01, indicating that overall available skylight to the room’s glazing as a whole is not reduced. ….. Given the dominant contribution of the extensive rear glazing (W2-W24) to the room’s daylighting, and the fact that none of these windows suffer any material loss as a result of the development, it is reasonable to conclude that the room as a whole is likely to continue to receive good levels of daylight from its primary orientation. This observation is supported by the weighted VSC analysis.”
[74]It is now known that the kitchen and two conservatories are not one room. The council and IP1 say this does not affect the officer’s conclusion that there will be no material effect on the lighting to the kitchen. In essence, they say, the officer’s point was that the development would have no impact on the ability of the conservatories, which were the main sources of light to the kitchen, to receive daylight.[75]Clearly, the officer considered that the conservatory glazing was the dominant source of light to the kitchen. Equally clearly, the daylight to the glazing to the conservatories was not affected by the development. However, I think a material part of the officer’s reasoning was the weighted-average analysis in the impact assessment, which suggested that there would be no loss of daylight in the kitchen, and in fact a slight increase.[76]That weighted-average analysis was clearly wrong. The BRE guide provides at para 2.2.8 for the various windows in a room to be taken into account when they are not more than 5m apart. As I have said, there was no evidence before me on whether the other windows are within 5m of window W1. However, in any case the fact is that the kitchen is separated from one conservatory by a wall, albeit a wall with a window (of whose width I saw no evidence), and from the other conservatory by glazed sliding doors. This means that the premise on which the weighted-average analysis proceeded, that the kitchen and conservatories were all one room, is false. Thus, there was a mistake of fact, which is uncontentious and objectively verifiable. The first and second tests in E v SSHD are met.[77]It was pointed out at the hearing that the BRE report states that there are no established guidelines to account for the fact that the daylight from the conservatory windows comes through a window in the case of one conservatory and through sliding doors in the other, as opposed to all the windows being in the same room. That is true, but I have seen no evidence that the fact that there are no established guidelines to deal with the actual situation at no 53 prevents a professional analysis being made based on that actual situation. The fact is that the premise on which the weighted average analysis was based was false, as the kitchen and the conservatories were not in one single room.[78]It follows that it is at least arguable that the officer report was vitiated by a material mistake of fact, thus satisfying the fourth test in E v SSHD. As is clear from E v SSHD, the mistake does not need to be decisive; it only needs to be material.[79]The council and IP1 suggested that the third test in E v SSHD is not met, as the claimant was at least partly responsible for the mistake, by sending to the council the flyaround images which showed the area lit by W1 as having no internal walls.[80]I do not think the claimant can be held responsible for the mistake on this basis. It was, or should have been, obvious that the purpose of the “flyaround” images was not to show interior walls. As the claimant pointed out, it was plain that the “flyaround” images were not meant to show walls, because of the lack of a front external wall to the house on the images.[81]Furthermore, it was pointed out that in her objections to the Rowland report the claimant did not refute the statement in that report that:
“It is fair to presume that the rear conservatory is open to the kitchen internally and that the main source of light for the kitchen is the rear elevation of the house, which is south facing, and not the north facing side window.”
[82]The claimant did not dispute that the main source of light is the rear elevation (i.e. the conservatories). Also, I do not think the statement that the rear conservatory was “open to the kitchen” internally necessarily meant that the kitchen and conservatories were all one room, so I do not think the claimant can be criticised for failing to dispute that statement. The rear conservatories are open to the kitchen, in the sense that they give light to the kitchen via a window and sliding glazed doors.[83]It is also said that though the impact assessment said at para 7.1 that the “results show that the windows and associated room [singular] will not experience a notable reduction in daylight”, and the claimant did see the impact assessment before the application was determined but did not point out to the council that the relevant windows serve more than one room.[84]Only 72 hours or three days elapsed between the impact assessment being uploaded onto the council’s website and the planning application being determined. It was not obvious from the impact assessment that the weighted-average analysis was based on all the windows being in one room, and it was not reasonable to expect the claimant to commission, receive and submit to the council an expert critique of the impact assessment in the short time between uploading of the impact assessment and determination of the application.[85]Addressing section 31 (3C) of the Senior Courts Act 1981, I cannot say that it was highly likely that the outcome for the claimant would not have been substantially different had the error not been made. Had the erroneous weighted-average analysis not been provided to the council, it is – at least arguably – not possible to know what the conclusions of the impact assessment would have been or what the officer responsible for the delegated report would have decided.[86]I refer lastly to the lowering by the claimant of the fence outside window W1 and removal of the trellis. This appears to have taken place after submission of the application. The suggestion for the council and IP1 was that the claimant did this deliberately to bolster her case against the application. It is likely that these actions increased the level of daylight to W1, but in the absence of evidence of the pre-existing level it is impossible to compare the daylight to W1 before and after the actions. I cannot therefore draw any conclusions from this point.[87]Overall, for the above reasons, it is arguable that the grant of planning permission was vitiated by a material mistake of fact. Failing to take account of the resident’s health condition and failure to perform the PSED.[88]It was not disputed that a resident of no 53 – Mr Davis – suffers from a disability which means that he has a protected characteristic under the Equality Act 2010.[89]As the council and IP1 say, one objection is referred to in the officer report, which must be that from the claimant. The claimant repeatedly stated in her objection submissions, including those of 23 December 2025 and 18 January 2026, that an inhabitant was CEV. I understand that her submissions were sent to the case officer who drafted the officer report. Furthermore, it is specifically stated in the officer report that the PSED has been considered.[90]I accept that as held in Bolton Metropolitan Borough Council v Secretary of State for the Environment [2017] PTSR 1091 (1995), a planning decision-maker is not obliged to refer to every material consideration, however insignificant, and to deal with every argument, however peripheral. I also accept that personal circumstances are not necessarily a mandatory material consideration. However, it is at least arguable that where the PSED applies, it must be clear that it has been fulfilled.[91]In my judgment it is arguable that in the present case the officer concerned did not fulfil the PSED. It is clear that the duty must be exercised in substance and with rigour. It is not a question of ticking boxes. The mere mention of the PSED does not show that the duty has been exercised. I saw no evidence that there had been a rigorous consideration of the duty, with a proper appreciation of the potential impact of the decision.[92]I appreciate that IP1 does not accept that the impact of granting planning permission would have the impact claimed by the claimant. However, I am not convinced that the need to give rigorous consideration to the duty was properly fulfilled.[93]In those circumstances it is arguable that the grant of planning permission was vitiated by failure to perform the PSED. Permitted development rights[94]There was no evidence before the council of intention by the IPs to implement their permitted development rights if permission were not granted for the development applied for. Nevertheless, it seems to me that the realistic prospect that a fall-back position will be implemented does not necessarily need to be established by evidence of intention by the owner of the site in question. It may in some cases be obvious that if planning permission for development X is not granted, development Y will be carried out instead.[95]In this case, I had no evidence about the likely practicability or utility of an extension complying with permitted development rights. Although I think it is obvious that the IPs would seek to implement the development applied for if permission was granted, it was not clear from the evidence before me how a development pursuant to the permitted development rights referred to in the officer report would compare with the development applied for – in other words whether it would be practicable and if practicable, useful.[96]This may have been because although the council and IPs fairly agreed to the claimant raising at the hearing before me her new ground of the reference in the officer report to permitted development rights, they were taken by surprise. Also, this is the permission stage, and the council and IPs will have the opportunity to submit evidence subsequently.[97]Nevertheless, on the basis of the material before me, I conclude that it was at least arguably not obvious that there was a realistic prospect of the fall-back development of a side extension being implemented if planning permission were not granted for the application.[98]It is therefore arguable that the grant of planning permission was vitiated by the fact that the decision-maker took account of the fall-back position. INTERIM RELIEF[99]As to interim relief, it will be evident from the foregoing that I think there is a serious issue to be tried.[100]As to the balance of convenience, the claimant’s case is that if the development proceeds, the effect on the disabled resident of no 53 – Mr Davis – will be very damaging. She says the development would cause “irreparable harm” and says in particular that it would make it impossible to administer Mr Davis’s medication in the kitchen and “render the kitchen unsafe for the resident’s medical care and recovery from strokes”. The claimant also said at the hearing before me that there is nowhere else in the house where Mr Davis’s medication can be administered, as natural light is needed and the house’s only other available windows are either on the street where there is no privacy and no available worktop, or in the conservatories, which are too hot.[101]However, these claims were no more than assertions. It does appear that Mr Davis has suffered from thalamic and cerebellar strokes and is regarded as CEV (or at least was so regarded at the time of the Covid pandemic), but there was no medical evidence (which I would have expected) to support the claimant’s assertions about the effect of the proposed development on him. Furthermore, as I have said it is likely that the recent lowering by the claimant of the fence outside window W1 and removal of the trellis increased the level of daylight to W1 from its previous level. This may to some degree compensate for the effect of the development.[102]Also, the delay until this claim is finally determined need not be substantial. If the IPs (or a successor if the IPs sold no 51) implemented the scheme before the final hearing of this matter, they would do so at their own risk. This is because if the development were built and then the permission was quashed at the substantive hearing of this matter, enforcement action by the council could require removal of the extension. If the development as implemented were seriously harmful to Mr Davis (or, indeed, to any other occupant of no 53) the council could be expected to take such enforcement action.[103]Overall, on the material I have seen, the alleged effect on Mr Davis does not justify the grant of interim relief. Furthermore, I am not convinced that any other of the claimant’s assertions about the detrimental effects of the development justifies interim relief.[104]IP1’s case is that delay to being able to implement the development may lead to increased construction costs and would in any case delay to the IPs the amenity value that the development will afford no 51. IP1 also says there is a public interest in respect for the grant of planning permission by local planning authorities, and weight should be placed on members of the public being able to rely on such decisions.[105]As I have already said, the delay until the final hearing of this claim need not be substantial, so I give some, but limited, weight to the effect of that delay on the IPs and to the public interest in respect for the grant of planning permission by a local planning authority. However, most importantly to my mind, the claimant’s case does not justify the grant of interim relief, for the reasons I have set out above. Therefore, overall, the balance of convenience lies against granting interim relief. OVERALL CONCLUSION[106]The claim is arguable in respect of mistake of fact, failure to perform the PSED and the officer’s reliance on permitted development rights. For the reasons I have given, I do not consider it appropriate to grant interim relief.[107]I will send to the parties with my draft judgment a suggested order. I will consider submissions for additional or alternative wording.