Thomas Armstrong (Aggregates) Limited v Secretary of State for Housing, Communities and Local Government & Ors

In the statutory review of old mineral permissions, a permission must remain valid and must authorise the relevant minerals development. Listing land under Schedule 13 of the Environment Act 1995 is administrative and preliminary. It does not conclusively establish that a valid relevant planning permission exists.

The Pilkington principle applies where physical alteration of land makes it impossible to carry out the development authorised by an earlier permission in accordance with its terms. That may include a fundamental change to the nature of the land, not merely a conflict between conditions. A permission granted only in principle, subject to approval of full details, does not authorise specific minerals development for the purposes of the ROMP regime.

The claimant challenged an inspector’s decision concerning a ROMP application under paragraph 9 of Schedule 13 to the Environment Act 1995. The application related to a 1954 permission for the continued working of High Close Quarry.

The site comprised Green Land, where quarrying had taken place and the quarry void was later infilled and restored, and Blue Land, where permission in principle had been granted but the required details had never been approved. The inspector concluded that the 1954 permission was not a relevant planning permission for either area. The central issues were whether the permission had become incapable of implementation, whether the ROMP powers could alter its conditions, and whether the Blue Land was covered by a relevant permission.

1. The claim was dismissed. The 1954 permission was not a relevant planning permission for the purposes of Schedule 13.
2. The claimant could not raise new factual evidence about methods of working that might have enabled compliance with conditions 4 and 6. Applying Barker Mills Estates v Test Valley BC [2017] PTSR 408 at [77], the proposed argument would have required factual evidence and findings before the inspector. It was therefore wrong to raise it on statutory review.
3. The inspector had lawfully applied the principle in Pilkington v Secretary of State for the Environment [1973] 1 WLR 1527. The permission was for the continued working of an existing quarry. The later landfill and restoration had removed the quarry void and quarry floor. Reading the permission as a whole, and from the perspective of a reasonable reader, it was physically impossible to carry out the authorised development in accordance with its terms. The conclusion did not depend solely on conditions 4 and 6.
4. The caution in Hillside Parks Ltd v Snowdonia National Park Authority [2022] UKSC 30 against applying the principle rigidly did not assist the claimant. The present facts involved a fundamental alteration in the nature of the land, and the Hart Aggregates and Whitley line of authority concerned a different question: compliance with pre-commencement conditions.
5. Once the permission was found not to be a relevant planning permission, the powers under paragraphs 9(6) and 9(7) of Schedule 13 to amend or substitute conditions did not arise. The ROMP regime could not resurrect an invalid or no longer extant permission.
6. For the Blue Land, the court followed the highly persuasive reasoning in LaFarge Aggregates Ltd v Scottish Ministers [2004] UKSC 524. A relevant planning permission must authorise specific minerals development. Permission in principle, subject to approval of full details that had never been submitted or approved, was insufficient.
7. G Hamilton (Tullochgribban Mines) Limited v The Highland Council [2012] UKSC 31 concerned the physical extent of land covered by a listed permission, not whether the permission remained valid or authorised the development in question. Its description of listing as administrative and preliminary was inconsistent with the claimant’s argument that listing was determinative.

This was a first-instance statutory challenge to an inspector’s decision dated 16 June 2025. The claim was dismissed.