This chapter in the appeal was presented as a criticism of the approach adopted by the majority of the judges in the court below. But that criticism comes at the most to criticism of particular expressions rather than any allegation of error in principle. Lord McCluskey criticised the description given by the Reporter in paragraph 181 of his decision letter of the effect of the section. His Lordship stated:

"But section 18A did not simply 'enhance the status' of development plans; it made the development plan the governing or paramount consideration; and it was to remain so unless material considerations indicated otherwise."

      But while the expression used by the reporter may have been somewhat imprecise in not stressing the priority inherent in the enhanced status it does not appear that the reporter fell into error in any misunderstanding of the effect of the section. The submission made by counsel for the Secretary of State on the construction of section 18A was correctly seen by the respondents as not constituting any serious attack on the decision which they sought to defend. The judges in the Second Division correctly recognised that it was competent for the Reporter in principle to decide that the more recent material should overcome the priority given to the development plan. The issue was whether he was entitled to take that course on the material before him. The reference to paragraph 181 of the decision letter leads immediately to the substantial dispute in the appeal regarding the reporter's treatment of the problem of retail trade and impact.

      In paragraph 181 the Reporter begins to set out his conclusions on the chapter of the decision letter which concerns the issue of retail trade and impact. It should be observed at the outset that the structure plan of 1985 indicated a prohibition of developments such as that proposed by Revival except in existing or new shopping centres, and that S.W.E.L.P. expressed at least a presumption against out-of-centre shopping development. The Reporter however stated:

"Dealing first with the question of policy, I should say that, although there is no dispute that the statutory development plan consists of the 1985 structure plan and the S.W.E.L.P., and although recent legislation enhances the status of development plans, I believe that in this case it is appropriate to attach greater weight to other material considerations."

      That he was entitled in principle to decide that the presumption in favour of the development plan had been overcome by other material considerations was recognised in the court below. The criticism of the majority of the court was directed rather at his entitlement to take that course in the circumstances of this case. The other material considerations to which the Reporter looked consisted of expressions of policy and planning guidance more recent in date than the structure plan of 1985. He noted that while the S.W.E.L.P. was only adopted as recently as 1993 it was required to conform generally with the provisions of the 1985 structure plan. The more recent material of which the Reporter considered account should be taken consisted of the National Planning Guidelines 1986, Planning Policy Guidance of 1993 ("PPG6), and the latest version of the structure plan which had been finalised and sent to the Secretary of State but had not yet been approved. A view was expressed in the court below that it was not appropriate to have considered PPG6 because it applied to England and Wales and not Scotland. No question was raised in that regard in the present appeal and I refrain from expressing any view about it. The new version of the structure plan represented in the view of the Reporter the Regional Council's most recent thinking on the subject of retailing and it was to the policies set out in that document that he applied his mind.

      Chapter 7 of the new structure plan deals with shopping. In paragraph 7.37 it was stated that free-standing developments, such as large convenience stores, could generate unacceptable traffic levels and affect residential amenity. The paragraph later states that:

". . . new stores can only be justified to provide consumer choice or where there will be significant local population increase. . . . new developments outside existing or proposed centres should be permitted only if they meet strict criteria."

      The plan then sets out a policy identified as S17. That policy related to proposals for major retail developments not in or adjacent to existing or proposed strategic shopping centres. It is understood that the proposed development at Colinton Mains Drive is such a proposal. The policy provides that in considering such proposals "District Councils should be satisfied that all of the following criteria are met. . . ." There are then set out seven criteria of which only two need be quoted:

"A. Local shopping facilities are deficient in either quantitative or qualitative terms; . . .

"C. They would not, individually or cumulatively, prejudice the vitality and viability of any strategic shopping centre."

      The strategic shopping centres are listed earlier in the document, but it is unnecessary to refer to that in detail.

      The Reporter was satisfied that all of the seven criteria were met and it was on that basis that he granted the planning permission. It is with criterion A that the present dispute is concerned. The Reporter dealt with the matter of quantitative deficiency in paragraph 184 of his letter as follows:

"184 The first matter relates to quantitative or qualitative deficiencies in the area. It appears that there may be a slight increase in both population and expenditure per head on convenience goods in the near future in the study area, but the most obvious indicator of an expenditure surplus is the calculation that certain stores (notably Safeway at Cameron Toll, Morningside and Hunter's Tryst) are performing at levels significantly higher than company averages. Even allowing for the opening of stores at e.g. Straiton (which may be in doubt) and for turnover levels at Colinton Mains substantially higher than would probably be achieved by Tesco in a relatively small store, there would appear to be a quantitative case."

      In paragraph 185 he considered the matter of qualitative deficiency and took the view that the argument for such a deficiency was not strong. The case would accordingly have to rest on the basis of a quantitative deficiency. Finally in this part of his letter he added in paragraph 186:

"186. Many local residents and organisations claim that there is no need for either the proposed foodstore or the pfs. I accept that there is not a significant shortage of either, such as might establish a strong presumption in their favour in the public interest which might outweigh relevant objections, However, planning approval does not have to be based on a case of need. I have explained why I consider the policies in the more recent version of the structure plan are to be preferred, and there remains a general presumption in favour of development unless demonstrable harm is shown to interests of acknowledged importance."

      The majority of the judges in the Second Division held that the Reporter had erred in this part of his decision. The Lord Justice-Clerk was satisfied that the Reporter was entitled to regard the NPG and the draft structure plan as justifying a departure from the development plan but considered that the Reporter had not had a proper factual basis for overcoming the presumption in section 18A. In particular he considered that:

". . . merely to say that certain stores within the area are trading at exceptionally high levels does not justify the conclusion that there is a deficiency in local shopping facilities in the area in question."

      He noted that of the three stores mentioned in paragraph 184 only one, Hunter's Tryst, was, as the Reporter had recognised in paragraph 185, within the study area. He also noted that the Reporter had accepted in paragraph 186 that there was not a significant shortage of food stores or petrol filling stations. Lord McCluskey questioned whether the Reporter had properly addressed the problem of quantitative deficiency at all. "If he has then he has not even begun to explain how a quantitative deficiency coexists with no significant shortage and a failure to make out any case of need." He considered that even if a finding of a quantitative deficiency was justified the Reporter had given no indication as to why that circumstance should overcome the presumption in favour of the terms of the development plan. Both the Lord Justice-Clerk and Lord McCluskey suggested that the final words of paragraph 184 lacked the conviction of a positive finding.

      In my view it is critical to an understanding of the Reporter's decision to have a clear understanding of the concept of "quantitative deficiency." This is a matter of the interpretation of the policy S17. It may well be that the point was not made sufficiently clear in the presentation of the appeal before the Second Division. Certainly it appears that, as the Lord Justice-Clerk records, counsel were not at one as to what was meant by the reference to quantitative terms and it was on his own initiative that reference was made to paragraph 7.9 of the draft structure plan for a clue to its meaning. That paragraph starts with the sentence "In quantitative terms, demand is determined by trends in consumer expenditure. . . ." This is far from providing a definition but it does, as Lord Morison appreciated, point to the fact that it is consumer expenditure which is being considered as reflected in the turnover in the available shopping facilities. As I understand it from the helpful explanations given to us by counsel for the Secretary of State quantitative deficiency has to do with a comparison between the amount of shopping facility and the amount of customers. It seeks to express a situation where there is a shortage of shopping floorspace as compared with the number of customers in the locality. It is measured by reference to consumer expenditure. Quantitative deficiency is a concept different from that of need, where what is meant is the kind of necessity which would, for example, justify the sacrifice of some amenity for the purpose of the development. There can be a quantitative deficiency even although there is no "need" for the development in so far as everyone in the area is able to do their shopping albeit with the delay and inconvenience of a possibly overcrowded shop or of travelling some distance to get there. Once the definition is understood there is no discrepancy between paragraphs 184 and 186 of the decision letter.

      The next question is how a quantitative deficiency should be established. Where the approach is one of considering consumer expenditure a quantitative deficiency is most readily established by the discovery that other stores are trading at a level which is above what would be expected of them, the inference being that there is room to accommodate a further shopping facility. As Lord Morison observed: "No other way of demonstrating a quantitative deficiency in a particular area, determined only by consumer expenditure, was suggested to us, and none occurs to me." That was the kind of evidence which was led in the present case and it appears that while there was dispute about the reliability of the inferences to be drawn from the figures adduced there was no objection taken to the use of that material in principle as a method of establishing the alleged deficiency.

      It was suggested that the Reporter was not entitled to find some deficiency without going on to quantify the extent of the deficiency. I see no obligation on him to do that. The policy S17A does not require the finding of any particular extent of the deficiency. If the deficiency is too slight to enable the whole of the proposed new shopping facility to be accommodated then the matter will be covered by criterion C. If the development is greater than can be absorbed by the deficiency then the result may well be to cause prejudice to the vitality and viability of the existing strategic shopping centres. In that respect criterion C secures the adequacy of the extent of the deficiency identified for the purpose of criterion A. In the present case the Reporter indeed went further in his assessment of the deficiency than he strictly needed to go. In the final sentence of paragraph 184 he takes into account not only the possible further store at Straiton but also higher levels at the development site at Colinton Mains than were likely to be achieved by the proposed Tesco store. Even taking these into account he finds that "there would appear to be a quantitative case." It is evident from that passage that the deficiency was such as to enable the proposed store to be wholly accommodated within it and when account is taken of the hypothesis on which he is proceeding the passage indicates a very positive finding of a quantitative deficiency. What was suggested to be only a tentative finding is in reality clear and certain.

      It was argued that the Reporter was not entitled to draw the conclusion which he did from the evidence before him. Counsel for the Respondents suggested a variety of reasons which might account for the expenditure surplus. He also sought to criticise the quality of the evidence on which the Reporter had relied. But it was not suggested that there was no evidence before the Reporter which could entitle him to discount such other explanations and to hold that there was an expenditure surplus which pointed to a quantitative deficiency. Whether the evidence did or did not so point was a matter wholly for him to determine. Provided that the evidence was there it was for him to assess it and draw his own conclusions from it. It is no part of the function of a reviewing court to re-examine the factual conclusions which he drew from the evidence in the absence of any suggestion that he acted improperly or irrationally. Nor is it the duty of a reviewing court to engage in a detailed analytic study of the precise words and phrases which have been used. That kind of exercise is quite inappropriate to an understanding of a planning decision.

      Counsel for the Respondents also sought to argue that the Reporter had not given proper or adequate reasons for his decision. In part this point was related to matters to which I have already referred, such as a specification of the extent of the deficiency, the allegedly "tentative" nature of the conclusion on the critical issue, the finding of the quantitative deficiency in the face of the absence of need, and the link between the expenditure surplus and the quantitative deficiency. But in any event the pursuit of a full and detailed exposition of the Reporter's whole process of reasoning is wholly inappropriate. It involves a misconception of the standard to be expected of a decision letter in a planning appeal of this kind. As Lord President Emslie observed in Wordie Property Co. Ltd. (p. 348):

"The decision must, in short, leave the informed reader and the court in no real and substantial doubt as to what the reasons for it were and what were the material considerations which were taken into account in reaching it."

      It is worth re-iterating the observations made by Lord Lloyd of Berwick in Bolton Metropolitan District Council v. Secretary of State for the Environment (1995) 71 P.Q.C.R. 309 in the context of the requirement on the Secretary of State to notify the reasons for his decision. His Lordship said (p. 313):

"There is nothing in the statutory language which requires him, in stating his reasons, to deal specifically with every material consideration . . . He has to have regard to every material consideration; but he need not mention them all."

      As to what should be mentioned his Lordship gave two quotations. In In re Poyser and Mills' Arbitration [1964] 2 Q.B. 467 at p. 478 Megaw J. said:

"Parliament provided that reasons shall be given, and in my view that must be read as meaning that proper, adequate reasons must be given. The reasons that are set out must be reasons which will not only be intelligible, but which deal with the substantial points that have been raised."

      In Hope v. Secretary of State for the Environment (1975) 31 P. & C.R. 120 at 123 Phillips J. said:

"It seems to me that the decision must be such that it enables the appellant to understand on what grounds the appeal has been decided and be in sufficient detail to enable him to know what conclusions the inspector has reached on the principal important controversial issues."

      It is necessary that an account should be given of the reasoning on the main issues which were in dispute sufficient to enable the parties and the court to understand that reasoning. If that degree of explanation was not achieved the parties might well be prejudiced. But elaboration is not to be looked for and a detailed consideration of every point which was raised is not to be expected. In the present case the Reporter dealt concisely but clearly with the critical issues. Nothing more was to be expected of him.

      The Reporter satisfied himself as he was entitled to do that there was quantitative deficiency and that criterion A was met. He then went on to consider the other criteria. He gave careful consideration to criterion C, including in that an assessment of the effect of the development on Hunter's Tryst and at some length its effect on the shopping centre at Wester Hailes. He was satisfied that criterion C was met and no challenge is made to that conclusion. His unchallenged finding on that matter affirms the adequacy of the deficiency which he found for the purpose of criterion A. He had already decided that the statutory presumption should be overcome by the more recent expressions of policy and in particular the draft structure plan. It was the existence of that recent guidance, not his finding of a quantitative deficiency, which justified the overcoming of the presumption. It is not in dispute that if the seven criteria were met the Reporter was then entitled to grant planning permission.

      For the foregoing reasons I would refuse the appeal by the appellant Revival Properties Limited on the matter of the listed building consent and I would allow the appeal by both appellants on the matter of the planning permission.

      The Secretary of State should be entitled to his costs from the District Council both here and one half of his expenses in the court below. Revival Properties Limited should be entitled to one half of their costs from the District Council here and one half of their expenses in the court below.