B e f o r e :
MRS JUSTICE LANG DBE ____________________
____________________
Hashi Mohamed and Edward-Arash Abedian (instructed by Wiltshire Council) for the Claimant Jonathan Darby (instructed by the Government Legal Department) for the First Defendant Christopher Young KC and Anna Stein (instructed by Wilsons Solicitors LLP) for the Second Defendant Hearing date: 10 February 2026 ____________________
HTML VERSION OF APPROVED JUDGMENT ____________________
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Mrs Justice Lang:
The Claimant applies for planning statutory review, pursuant to section 288 of the Town and Country Planning Act 1990 ("TCPA 1990"), of the decision of an Inspector, appointed by the First Defendant ("D1"), dated 9 April 2025, to allow the appeal of the Second Defendant ("D2") against the Claimant's refusal of outline planning permission on land at Old Sarum Airfield, Old Sarum, Salisbury SP4 6FW ("the Site").
The Claimant's grounds of challenge may be summarised as follows:
i) Ground 1: the Inspector's decision is unsound, as it is based on a materially incorrect basis of fact, following the change of circumstances brought about by extensive fire damage to Hangar 3 which occurred shortly after the Inspector's decision.
ii) Ground 2: the Inspector's decision has been vitiated by external injustice as a result of the fire and damage to Hangar 3.
Kerr J. granted permission on the papers on 5 October 2025.
Planning history
Old Sarum Airfield ("the Airfield") operates as a commercial/civilian airfield. It has been identified by Historic England as one of the best-preserved flying fields of the First World War ("WW1") period with one of the most complete suites of technical and hangar buildings. It is of significant heritage importance. The Airfield was designated a Conservation Area in 2007, and contains three Grade II* listed former WW1 aircraft hangars, as well as further Grade II listed buildings.
The easternmost of the listed hangars - Hangar 3 - is within the Site. Its condition has deteriorated considerably over many years such that it is now considered a category 'A' priority building ("Immediate risk of further rapid deterioration or loss of fabric") in "Very bad" condition on Historic England's 'Heritage at Risk' Register.
Core Policy 25 ("CP25") of the Wiltshire Core Strategy ("WCS"), adopted in January 2015, allows for sympathetic new development on the Airfield perimeter, where proposals can demonstrate that they will deliver the outcomes identified in the policy.
For several years, D2 has sought to bring forward development on the Site. In 2019 an appeal was dismissed by a planning inspector, in large part due to the "inordinate amount of harm to the heritage assets" that would be caused by the proposal and conflict with CP25. In reaching her decision, Inspector Mahoney accorded considerable weight to securing the restoration of Hangar 3. D2 challenged this decision in the High Court without success.
D2 made a second application for planning permission in September 2023 (the subject of this claim), which differed from the first application in a number of respects. The application was as follows:
In a consultation response to the application, dated 3 November 2023, Historic England expressed its view that the heritage harms identified previously by Inspector Mahoney could be overcome by a restoration of Hangar 3, although there was insufficient evidence as to the viability of such a restoration, and therefore an application for Listed Building Consent with a costed schedule of works was desirable.
In January 2024, D2 made a standalone application for Listed Building Consent for repair and refurbishment of Hangar 3. It was accompanied by a design report and cost plan. It had to be updated following storm damage.
On 23 February 2024, Historic England provided a response to the Listed Building Consent application, combined with an updated consultation response to the application for planning permission, which stated:
The Claimant granted Listed Building Consent on 11 March 2024. It was granted subject to conditions, including approval of details by the local planning authority. Condition 3 provided:
The informatives stated:
The Claimant refused the application for planning permission on 15 August 2024, for five reasons. The second reason was that the scheme would be of a significant height and scale and the open character of the site would be eroded. It would have a significant visual impact, and be likely to cause less than substantial harm, to the character and setting of the surrounding heritage assets, which is not outweighed by significant public benefits.
The Inspector's Decision
D2 appealed to D1 against the refusal of the application. Inspector Fagan held a 9 day public inquiry and a site visit. At paragraph 4 of the Decision Letter ("DL/4"), he identified four main issues for determination, namely: (1) whether development could in terms of financial viability deliver 25% affordable housing units; (2) the highways issue; (3) whether the development would result in any heritage harm and, if so, whether this harm would be outweighed by the public benefits; and (4) the planning balance: whether other material considerations would outweigh any conflict with the development plan, either in terms of the standard or tilted balance.
During the appeal, the Claimant argued that D2 should not be permitted to take advantage of the need to restore Hangar 3 as a benefit of the scheme, as it had failed to maintain it. The Inspector found as follows:
Inspector Fagan's conclusions on the heritage balance were as follows:
The Inspector undertook the planning balance at DL/96 – 104. He identified the benefits of the scheme at DL/96 – 100, in addition to the heritage benefits already identified. He considered that the scheme would comply with CP25 and other Core Strategy policies listed, and as it would accord with the development plan, there was no reason to withhold planning permission.
As part of the grant of permission the Inspector imposed a condition to secure the repair and restoration of Hangar 3. Condition 17 imposes a series of restrictions precluding occupation of residential units on the Site until those restoration works are completed. It provides as follows:
The Inspector sent the DL to the parties on 9 April 2025. Costs decisions were sent in a separate decision letter dated 17 April 2025.
The fire
On the evening of 17 April 2025, Hangar 3 caught fire, together with the café and another adjacent building. The incident report from Dorset and Wiltshire Fire & Rescue recorded the "Cause/motive" as "Deliberate". Subsequently, Dorset & Wiltshire Fire Service and Dorset & Wiltshire Police conducted a formal investigation into the cause of the fire, and considered whether it was caused deliberately or accidentally. On 23 October 2025, the police officer leading the investigation informed Mr Grenville Hodge, a Director of D2, that the police investigation had been closed down in the light of the fire report which stated:
D2 made a claim to its insurers, Aviva, in respect of the fire damage to the buildings other than Hangar 3 (which was uninsured). Aviva commissioned an investigation into the cause of the fire but did not disclose any findings to D2. On 27 June 2025, Aviva notified D2 that the investigation had concluded and loss adjusters had been instructed to assess the loss. D2's claim was subsequently met in full by Aviva. In my view, on the balance of probabilities, Aviva's willingness to pay the claim, without any further questioning of D2, indicates that its investigation did not conclude that D2 was responsible for the fire, whether deliberately or negligently.
In the light of the outcome of these investigations, I consider it is not possible to proceed on the basis that the fire was or may have been set deliberately.
Application to discharge condition 3 of the Listed Building Consent
On 5 November 2025, D2 submitted an application to discharge condition 3 of the Listed Building Consent. The application was accompanied by a structural survey report for Hangar 3, a design and condition report, and a revised Stage 3 cost plan.
The structural survey (September 2025) was limited to a visual structural inspection without "intrusive inspection of the building fabric". The report states that it is possible to reconstruct Hangar 3, and the extent of work required is not significantly different to the situation before the fire. It states at Chapter 6:
The updated Design and Condition Report (September 2025) concludes that "the fire has not fundamentally altered the scale or methodology of the restoration". It notes the changes to the previously approved works as follows:
The Stage 3 Cost Plan (revised 29 October 2025) estimates the total cost (including construction costs, contingency, design risk and inflation) at £4.43 million. The construction costs alone, prior to the fire, amounted to £2,601,511.81. The additional work required after the fire will cost £688,638.75. The total construction costs are now estimated at £3,290.150.56. Based on these estimates, the costs have risen by approximately a third (£1.1 million) from the £3.31 million figure presented to the Inspector at the Inquiry.
Mr Guest, who is the Claimant's Conservation and Design Manager, expressed the view in paragraph 26 of his witness statement dated 19 May 2025, that because of the fire damage to Hangar 3, the Listed Building Consent is no longer fit for purpose. In his view, it followed that condition 17 to the planning permission cannot now be actioned which would render the whole planning permission unimplementable. However, his evidence pre-dated D2's updated reports and costs estimates which were submitted to the Claimant in support of the application to discharge condition 3 of the Listed Building Consent on 5 November 2025. The Claimant has not filed any evidence in response.
The application to discharge condition 3 of the Listed Building Consent has been registered by the Council but has not yet been determined.
Grounds of challenge
Ground 1
Claimant's submissions
The Claimant submitted that the authorities were clear that when new evidence comes to light which could not have been made available to the decision-maker, or other exceptional circumstances exist, then the court can take fresh evidence into account when exercising its powers of review. This is not limited to errors of fact or new evidence which existed prior to the decision under challenge.
The Claimant relied on the following authorities. E v Secretary of State for the Home Department [2004] EWCA Civ 49 , [2004] QB 1044 , at [66]; R (Powis) v Secretary of State for the Environment [1981] 1 WLR 584, at 595-6; R (Law Society) v Lord Chancellor [2019] 1 WLR 1649 ; R (Connolly) v Havering LBC [2008] EWHC 2873 (Admin) , at R (Albert and Maud Johnson Trust Ltd) v West Sussex Quarter Sessions [1974] QB 24; R (Al-Mehdawi v Secretary of State for the Home Department [1990] 1 AC 876 ; R (Momin Ali) v Secretary of State for the Home Department [1984], 1 WLR 663; R (Launder) v Secretary of State for the Home Department (No. 2) [1997] 1 WLR 839 , at 860H-861A; R (Fidler) v Secretary of State for Communities and Local Government [2011] EWCA Civ 1159; and ATE Farms Limited v Secretary of State for Housing, Communities and Local Government [2025] EWHC 347 (Admin) .
In E, which is the leading authority on mistakes of fact in a public law context, Carnwath LJ, giving the judgment of the court, stated:
The Claimant submitted that the criteria in E were met, for the following reasons:
i) There is a mistake of fact because the Inspector's decision was predicated on the condition of Hangar 3 as it existed at the time of the inquiry, which is now materially incorrect because of the damage caused by the fire.
ii) The fact that there has been a fire which has damaged Hangar 3 is uncontentious.
iii) The Claimant is not responsible for the mistake of fact.
iv) The mistake of fact was material to the Inspector's reasoning; he considered that the restoration of Hangar 3 was of central importance to the decision to grant planning permission.
The Claimant emphasised that the Inspector's decision to grant planning permission in this case was made at a specific point in time and on the basis of a clearly defined understanding of the factual context. Those facts, which the Inspector understood to be the reality, were superseded (or at very least were materially impacted) by an intervening act which occurred only 8 days after he made his decision, and within the 6 week period to bring a statutory challenge. This case therefore falls within the situation described by Lord Hope in Launder as justifying the court's intervention, and one of exceptional circumstances in line with Momin Ali and E .
The Claimant also submitted that the fact of the fire, its cause and the prospects of restoring Hangar 3 were material considerations which ought to be re-considered by the Inspector, given the importance of the Site. Furthermore, if the Inspector were to re-consider his decision, in the light of the fire damage and the new evidence from D2 on repair and reconstruction, the heritage balance and the planning balance might well be different.
Conclusions
Under section 288 TCPA 1990, a person aggrieved may apply to quash a decision on the grounds that (a) it is not within the powers of the Act; or (b) any of the relevant requirements have not been complied with, and in consequence, the interests of the applicant have been substantially prejudiced.
The general principles of judicial review are applicable to a challenge under section 288 TCPA 1990. Thus, the Claimant must establish a public law error on the part of the D1 when making the challenged decision.
I accept the submissions of D1 and D2 that this ground has no merit. The Inspector's decision does not disclose any error of law or mistake of fact. It was taken on a correct application of the law to the facts as they existed at the time, as the Claimant concedes. A subsequent event, such as the fire, cannot retrospectively render a lawful decision unlawful.
In my view, it is irrelevant that the subsequent event occurred within the 6 week period to bring a statutory challenge. That was merely a matter of chance. If, contrary to my view, the court had jurisdiction to quash a prior decision in circumstances such as these, it is hard to see how a fair distinction could be made between a fire which occurred before or after the expiry of the 6 week period. Such a fundamental change to existing legal principles would inevitably undermine the certainty of planning decision-making, which developers rely upon.
In Powis , at 595G, Dunn LJ set out the accepted principles (as at that time) upon which fresh evidence should be admitted on judicial review, namely, (1) to show the nature of the material before the decision-maker; (2) to determine a fact on which jurisdiction depended or whether essential procedural requirements were observed; and (3) to prove alleged misconduct by one of the parties or the tribunal. In the Law Society case, the Divisional Court held:
The case of E was solely concerned with a mistake of fact which had occurred and was discoverable before the challenged decision was taken. The issue was whether "new evidence" could be relied upon to demonstrate the mistake of fact. The Court said, at [91]:
Here, there is no "new evidence" which demonstrates a mistake of fact by the Inspector at the time when he made his decision because the fire damage did not exist at the date of the decision. The fire was a subsequent event. There was no unfairness in the Inspector's decision arising from a misunderstanding of "an established and relevant fact". This is a distinction of fundamental importance.
The other authorities cited by the Claimant do not support its submissions either.
Albert and Maud Johnson Trust concerned new evidence discovered post-trial on public use of a footpath which undermined the finding of fact made at Quarter Sessions. The Court of Appeal refused to quash the decision. Lord Denning said, in a dissenting judgment, that hitherto the cases had only allowed certiorari where the decision of the inferior court was vitiated by fraud or perjury, but the remedy should not be confined to those two grounds. It should also be allowed where the decision of the inferior court was vitiated by mistake of fact if fresh evidence was discovered which could not have been found with due diligence before the trial, where it is apparently credible and would have an important influence on the result. However, Lord Denning found that those criteria were not met in that case and declined to admit the new evidence. The passage in Lord Denning's judgment relied upon by the Claimant was an obiter dicta in a dissenting judgment, and clearly distinguishable from this case since the complaint was that the Quarter Sessions had made its findings on a mistaken basis, not that the original decision was correct, but that there had been a change of circumstances. Although the case is of historical interest, it has been superseded by E . The fact that Lord Denning's view was referred to (but not endorsed) by Lord Bridge in Al-Mehdawi does not alter that analysis.
Momin Ali concerned a challenge to the accuracy of an Adjudicator's finding, in favour of the claimant, that he was the sponsor's son, and therefore was eligible for leave to remain in the UK, in the light of post-decision fresh evidence that the claimant was actually the sponsor's nephew. Sir John Donaldson MR held, at 670D-F:
Thus, it was a challenge based upon the validity of the Adjudicator's original findings, not on the basis of a supervening event.
In Launder , the Secretary of State for the Home Department authorised the applicant's extradition to Hong Kong under sections 6(4) and 12 of the Extradition Act 1989. The House of Lords held that the Secretary of State had applied the correct test, namely, whether in all the circumstances it was unjust, oppressive or wrong to return the applicant; that his decision was not irrational; and that, in the circumstances, it could not be said that the Secretary of State had not taken fully into consideration whether to return the applicant would constitute a breach of the ECHR. The Secretary of State took into account new evidence as to events arising after the date of his initial decision
Launder has to be read in the context of the statutory scheme for extradition which conferred a "continuing duty" on the Secretary of State to keep the extradition under review and to withdraw the warrant should circumstances change. Obviously it may well be necessary to consider new evidence and to revise the original decision, in order to discharge this continuing duty.
The statutory scheme was summarised by Lord Hope at 852C-H:
Furthermore, Lord Hope went on to say, at 861A-B:
Launder pre-dated the Human Rights Act 1998. Following the enactment of section 6 of the Human Rights Act 1998, the court is a public authority which must act compatibly with Convention rights. The doctrine of proportionality requires the reviewing court to assess the balance which the decision-maker has struck, not merely whether it is within the range of rational responses ( R (Daly) v Secretary of State for the Home Department [2001] 2 AC 532 ). In doing so, the court is not limited to the evidence which was before the decision-maker (see cases cited at ' Judicial Review Handbook ' , Fordham (8 th ed.) at 17.12.16).
Convention rights are not engaged in this claim. The planning statutory scheme does not include a continuing duty comparable to that under the Extradition Act 1989. D1 was functus officio once the appeal decision was made. Therefore Launder is clearly distinguishable from this claim and does not lend support to the Claimant's submissions.
ATE Farms Ltd does not assist the Claimant either. The facts of that case and the chronology of events were materially different. The planning inspector made a preliminary ruling that an enforcement appeal could proceed, in part, despite an ongoing police investigation into the cause of the fire. In doing so, the planning inspector had considered that he would not need to hear evidence about or make a finding as to the cause of that fire in order to make his decision on the ground (a) appeal (i.e. deemed application for planning permission). A challenge was brought in relation to that preliminary ruling. However, Mould J. considered that, "on the face of the cases that the parties wish to advance at the appeal inquiry in relation to ground (a), no such possibility exist[ed]" (at [28]). He concluded:
It is clear from my judgment above, under the sub-heading "The fire", that such circumstances do not arise in this claim.
For these reasons, Ground 1 does not succeed.
Ground 2
Claimant's submissions
The Claimant submitted that the consequences of the fire were an example of external injustice or unfairness. Acts which post-date the decision under challenge are, in principle, capable of vitiating that decision. The examples in the case law are not a closed list and there is no established test to apply. The Claimant referred to the 7 th edition of ' Judicial Review Handbook ', Fordham (now superseded by the 8 th ed.), at paragraph 65.1:
The Claimant submitted that this principle was wide enough to encompass this situation, where it is not known whether the fire was deliberate or not. Damage to Hangar 3 has stripped the Inspector's decision of its logic and rendered the decision meaningless. The Site can now be developed without providing any of the heritage benefits that were promised. D2 now has an opportunity to avoid restoration of Hangar 3 in its entirety, or find a new argument to avoid providing the affordable housing previously agreed, because of the increased cost of restoration and repair following the fire. The Claimant does not accept D2's evidence that condition 3 of the Listed Building Consent and condition 17 of the planning permission can be discharged.
The analogy with the common law doctrine of frustration of a contract (mentioned by Kerr J.) was not pursued by the Claimant at the hearing, and therefore I have not addressed it.
The Claimant submitted that there are limited circumstances in which it will be appropriate to develop the limits of planning law, on public policy grounds. It cited Pioneer Aggregates (UK) Limited v Secretary of State for the Environment [1985] AC 132, per Lord Scarman at [140]:
Conclusions
I accept the submissions made by the Defendants.
The proposed development is governed by the terms of the Listed Building Consent and the planning permission. D2 can only implement the permission and the consent in accordance with the conditions attached. Condition 17 is designed to prevent the housing development being occupied until the repair and restoration work to Hangar 3 is completed. If D2 wants to vary the development, it will have to seek permission to do so from the Claimant, either by seeking to vary or discharge the existing conditions under section 73 TCPA 1990, or by making a fresh application for planning permission in different terms.
However, the Claimant's fear that D2 does not intend to repair and restore Hangar 3 is unsupported by any evidence. On the contrary, D2 has confirmed that it does intend to repair and restore Hangar 3. To that end, D2 has applied to discharge condition 3 of the Listed Building Consent, and it has submitted detailed surveys, reports and costings. These include a detailed breakdown of the additional works and expenditure required as a result of the fire. On the face of it, these documents amount to clear evidence that the Listed Building Consent and the planning permission can be implemented. The Claimant has not identified flaws in the evidence, nor filed any evidence to contradict it.
The next step is for the Claimant to consider and approve the proposed works under condition 3. If and insofar as it does not approve them, then planning officers should negotiate with D2 on suitable amendments, in accordance with standard practice. Informative 8 also raised the possibility of a further application if there were extensive additional works required, which is a fallback.
The planning officer's report for the grant of Listed Building Consent, in January 2024, identified the damage done by the January 2024 storm; warned that more works would be required if work was not commenced promptly; and advised that works to historic buildings in poor repair were usually impossible to define precisely in advance of commencement, and so a degree of flexibility of the consent granted was necessary. The Listed Building Consent was granted on that basis, and the Claimant ought not to resile from it. The unnecessary delay caused by this claim is regrettable.
If D2 has under-estimated the extent of the works and the costs, then it will have to consider its position, as owner of the Site and successful applicant for planning permission. Viability may be negatively impacted, but that would not necessarily render the permission unimplementable. It is premature to reach any conclusions.
In my view, there is no external injustice or unfairness which vitiates the Inspector's decision. The Inspector's decision is valid and is unaffected by the fire and its consequences. There is a satisfactory way forward, namely, by utilising statutory planning procedures to develop the Site, as outlined above.
For these reasons, Ground 2 does not succeed.
Final conclusion
The application for planning statutory review is dismissed.
The Claimant has agreed to pay the First Defendant's costs in the sum of £18,512.80, but resists any costs order in favour of the Second Defendant, applying the general principle in Bolton MDC v Secretary of State for the Environment [1995] 1 WLR 1176 , per Lord Lloyd, at 1178G – 1179A, that an unsuccessful claimant should not have to pay a second set of costs incurred by the developer. In my view, this case falls within the exceptions identified in Bolton , because there were issues which were not adequately covered by the First Defendant, and the Second Defendant had interests which required separate representation. The Claimant made a thinly-veiled attack on the bona fides of the Second Defendant, suggesting that it might decide not to restore the hangar (despite its stated intention to do so), and hinting that it may have been responsible for the fire. That clearly influenced Kerr J.'s decision to grant permission and the Second Defendant was entitled to respond to it. Furthermore, a significant part of the claim turned on events which arose after the Inspector's inquiry and decision, and so were not addressed by the Inspector. The Second Defendant adduced evidence, in November 2025, relating to the cause of the fire, and also expert evidence assessing the extent to which the fire damage added to the work required on Hangar 3, and the likely cost of the additional works. This was the only evidence on these issues, as the Claimant did not produce any evidence. It was essential to my understanding of the claim and my conclusions. Therefore, the Second Defendant is entitled to a costs order in its favour.
I agree with the Claimant that the costs claimed by the Second Defendant, in the sum of £59,104.00, appears excessive. Given the complexity of the claim, and the sums involved, I do not consider that the costs are suitable for summary assessment. Therefore I have ordered that there shall be a detailed assessment, if the costs cannot be agreed.