“The power of HMRC to make an assessment under section 29(1) following the discovery of what, for convenience, I shall refer to as an insufficiency in the self-assessment depends upon whether an officer ‘could not have been reasonably expected, on the basis of the information made available to him before that time, to be aware of the insufficiency’. It is clear as a matter of authority: (1) that the officer is not the actual officer who made the assessment … but a hypothetical officer; (2) that the officer has the characteristics of an officer of general competence, knowledge or skill which include a reasonable knowledge and understanding of the law: see HMRC v Lansdowne Partners LLP[2012] STC 544 ; (3) that where the law is complex even adequate disclosure by the taxpayer may not make it reasonable for the officer to have discovered the insufficiency on the basis of the information disclosed at the time: see Lansdowne at [69]; (4) that what the hypothetical officer must have been reasonably expected to be aware of is an actual insufficiency: see Langham v Veltema[2004] STC 544 per Auld LJ at [33]–[34]: ‘33. More particularly, it is plain from the wording of the statutory test in section 29(5) that it is concerned, not with what an Inspector could reasonably have been expected to do, but with what he could have been reasonably expected to be aware of. It speaks of an Inspector’s objective awareness, from the information made available to him by the taxpayer, of ‘the situation’ mentioned in section 29(1), namely an actual insufficiency in the assessment, not an objective awareness that he should do something to check whether there is such an insufficiency …; (5) that the assessment of whether the officer could reasonably have been expected to be aware of the insufficiency falls to be determined on the basis of the types of available information specified in section 29(6). These are the only sources of information to be taken into account for that purpose: see Langham v Veltema, at [36]: ‘The answer to the second issue - as to the source of the information for the purpose of section 29(5) - though distinct from, may throw some light on, the answer to the first issue. It seems to me that the key to the scheme is that the Inspector is to be shut out from making a discovery assessment under the section only when the taxpayer or his representatives, in making an honest and accurate return or in responding to a section 9A enquiry, have clearly alerted him to the insufficiency of the assessment, not where the Inspector may have some other information, not normally part of his checks, that may put the sufficiency of the assessment in question. If that other information when seen by the Inspector does cause him to question the assessment, he has the option of making a section 9A enquiry before the discovery provisions of section 29(5) come into play. That scheme is clearly supported by the express identification in section 29(6) only of categories of information emanating from the taxpayer. It does not help, it seems to me, to consider how else the draftsman might have dealt with the matter. It is true, as Mr Sherry suggested, he might have expressed the relevant passage in section 29(5) as “on the basis only of information made available to him”, and the passage in section 29(6) as “For the purposes of subsection (5) above, information is made available to an officer of the Board if, but only if,” it fell within the specified categories. However, if he had intended that the categories of information specified in section 29(6) should not be an exhaustive list, he could have expressed its opening words in an inclusive form, for example, “For the purposes of subsection (5) above, information … made available to an officer of the Board … includes any of the following”.’” ‘33. More particularly, it is plain from the wording of the statutory test in section 29(5) that it is concerned, not with what an Inspector could reasonably have been expected to do, but with what he could have been reasonably expected to be aware of. It speaks of an Inspector’s objective awareness, from the information made available to him by the taxpayer, of ‘the situation’ mentioned in section 29(1), namely an actual insufficiency in the assessment, not an objective awareness that he should do something to check whether there is such an insufficiency …; ‘The answer to the second issue - as to the source of the information for the purpose of section 29(5) - though distinct from, may throw some light on, the answer to the first issue. It seems to me that the key to the scheme is that the Inspector is to be shut out from making a discovery assessment under the section only when the taxpayer or his representatives, in making an honest and accurate return or in responding to a section 9A enquiry, have clearly alerted him to the insufficiency of the assessment, not where the Inspector may have some other information, not normally part of his checks, that may put the sufficiency of the assessment in question. If that other information when seen by the Inspector does cause him to question the assessment, he has the option of making a section 9A enquiry before the discovery provisions of section 29(5) come into play. That scheme is clearly supported by the express identification in section 29(6) only of categories of information emanating from the taxpayer. It does not help, it seems to me, to consider how else the draftsman might have dealt with the matter. It is true, as Mr Sherry suggested, he might have expressed the relevant passage in section 29(5) as “on the basis only of information made available to him”, and the passage in section 29(6) as “For the purposes of subsection (5) above, information is made available to an officer of the Board if, but only if,” it fell within the specified categories. However, if he had intended that the categories of information specified in section 29(6) should not be an exhaustive list, he could have expressed its opening words in an inclusive form, for example, “For the purposes of subsection (5) above, information … made available to an officer of the Board … includes any of the following”.’” 127. Patten LJ also endorsed, in paragraph 41, this passage from the decision of the Upper Tribunal (Norris J and Judge Berner) in Charlton v Revenue and Customs Commissioners[2013] STC 866 : “……. [79] As we have described, the balance provided by s 29 depends on protection being provided only to those taxpayers who make honest, complete and timely disclosure. That balance would be upset by construing s 29(6)(d)(i) too widely. Inference is not a substitute for disclosure, and courts and tribunals will have regard to that fundamental purpose of s 29 when applying the test of reasonableness.”
“59. It is also necessary to bear in mind that not all differences in treatment are relevant for the purposes of article 14. The difference is only relevant, for the purpose of assessing whether there has been discrimination, if the claimant is comparing himself with others who are in a relevantly similar situation. An assessment of whether situations are “relevantly” similar generally depends on whether there is a material difference between them as regards the aims of the measure in question.”