Thomas Armstrong (Aggregates) v Housing Secretary: when landfill buries a quarry's right to be reviewed

There is something almost archaeological about Thomas Armstrong (Aggregates) Ltd v Secretary of State for Housing, Communities and Local Government [2026] EWHC 1345 (Admin). At its centre is a planning permission granted in December 1954, for a quarry whose void was filled in and restored to fields in 1990, with the judgement noting that today there is little on the surface to suggest a quarry was ever there at all. The question for Mrs Justice Lieven was whether that 70 year old permission could still be brought within the Environment Act 1995's review of old mineral planning (ROMP) regime, decades after the land it authorised had physically ceased to exist.

The 1954 permission for High Close Quarry in Cumbria covered two areas. The "Green Land" had been actively quarried, its void later filled under a 1976 landfill permission and restored to agriculture by 1990. The "Blue Land" had permission "in principle" for quarrying, subject to a condition requiring detailed approval before work began, a condition that was never discharged and on which no quarrying ever took place. In 2019 the quarry owner applied under paragraph 9 of Schedule 13 to have new conditions determined for the 1954 permission. The planning inspector decided that, for both areas, there was no longer a "relevant planning permission" capable of being reviewed at all, and the owner challenged that conclusion.

On the Green Land, the judgement turns on the well known principle from Pilkington v Secretary of State for the Environment, refined more recently by the Supreme Court in Hillside Parks v Snowdonia National Park Authority. The 1954 permission was for "continued working" of an existing quarry, with conditions premised on a quarry void and quarry floor continuing to exist, governing where waste could be tipped and where plant could be sited. Once that void had been completely filled and the land restored, Lieven J found it physically impossible to carry out what the permission actually authorised. The quarry owner argued this was too blunt an approach, and that the correct question, drawn from Hart Aggregates v Hartlepool BC, was whether the relevant conditions went to the heart of the permission, with any genuine problem to be solved by varying conditions under section 73A. The judge rejected this distinction. Hart Aggregates dealt with non-compliance with pre-commencement conditions, a different question entirely from whether physical changes to the land have rendered a permission impossible to implement at all. Once impossibility under Pilkington is established, the ROMP power to vary conditions under paragraph 9(7) simply never arises, because there is no relevant permission left for it to attach to.

The Blue Land raised a separate and arguably more interesting point about "in principle" permissions, addressed through the Scottish case of LaFarge Aggregates v Scottish Ministers. The judgement accepts the broader reading of LaFarge: a relevant planning permission must authorise specific minerals development, not merely approve a principle subject to undischarged conditions. An in principle permission for an undefined area, where the detail was never approved, simply never crystallised into something the ROMP regime can review. The owner's fallback argument, that the Supreme Court's decision in Hamilton meant inclusion on the council's statutory list was itself determinative of validity, was given similarly short shrift. Hamilton addressed the physical extent of a listed site, not whether an underlying permission remained valid, and nothing in it suggested an intention to depart from the established line in Foster and Payne that an MPA can always look behind the list to check a permission's continuing validity.

The practical message is a sobering one for owners of long dormant mineral sites where intervening development, particularly restoration or landfill, has changed the character of the land. The ROMP regime exists to modernise conditions on permissions that are still alive, not to resurrect ones that physical reality has already extinguished. Anyone assessing the latent value of historic mineral permissions on restored land would do well to test, at an early stage, whether Pilkington's physical impossibility test might already have done the planning authority's work for it.