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Call for planning permission variations reform after Hillside ruling

Row of houses

Planning law in England should be updated to avoid a situation where the original planning permission granted to a site is invalidated by departures from the original approved plans because subsequent planning permissions granted for development within that site have made compliance with the original scheme physically impossible, an expert has said.

Jamie Lockerbie of Pinsent Masons said the reforms were necessary following a ruling by the UK Supreme Court (34-page / 315KB PDF). He said neither developers nor local planning authorities would welcome the judgment.

The Supreme Court rejected developer Hillside Parks Ltd’s appeal against an earlier Court of Appeal ruling which found against further development it planned at a site within Snowdonia National Park in Wales under its original permission.

Planning permission for development on the site was originally granted in 1967 for 401 houses. However, subsequent, separate, permissions for individual or small groups of dwellings were applied for and granted. None of the development that had taken place, amounting to 41 houses, conformed with the master plan in the 1967 permission.

Portrait of Jamie Lockerbie

Jamie Lockerbie


An already complicated corner of planning law just got even more complicated. To the extent there is an ‘easy’ answer to all of this I suggest it is one of legislative change

In 2017, Snowdonia National Park Authority informed Hillside that no further development work on the site could take place under the 1967 permission. The planning authority considered that the development works Hillside had already undertaken under the separate permissions departed too significantly from the 1967 permission master plan and that it was now physically impossible to build the development in accordance with that master plan. This, it said, meant the 1967 permission was no longer valid for the development to be carried out to completion.

Hillside challenged that decision before the courts, but the Supreme Court has now upheld the Court of Appeal’s finding that the further development would be unlawful. This is because it considered the further development could not be carried out in a way which was consistent with the original approved development for which planning permission had been granted.

At the heart of the Supreme Court’s decision was its consideration of the so-called Pilkington principle. The court considered that the principle is that earlier planning permission cannot be relied upon if successive permissions granted mean it is ‘physically impossible’ for that earlier planning permission to be granted. In the Hillside case, the location of housing and roads was different to that envisaged under the original plans.

The Supreme Court said that departures from the original plans must be “material in the context of the scheme as a whole” to satisfy the Pilkington principle.

“Rightly in our view, [Snowdonia National Park Authority] has not argued on this appeal that the continuing authority of a planning permission is dependent on exact compliance with the permission such that any departure from the permitted scheme, however minor, has the result that no further development is authorised unless and until exact compliance is achieved or the permission is varied,” the court said.

The Supreme Court said that it is “possible in principle for a local planning authority to grant a planning permission which approves a modification of such an entire scheme rather than constituting a separate permission referable just to part of the scheme”. However, it held that Hillside had not been able to demonstrate that the additional planning permissions under which development has been carried out at the site in question since the original planning permission was modified by the High Court in 1987 should be construed in this way. “In the absence of clear express provision making it severable”, the court said, it was not possible to infer the additional permissions formed part of the integrated whole.

Lockerbie said the ruling creates additional burdens for developers working on large multi-phase schemes where changes to part of the scheme are proposed to be secured by what is known as an overlapping or 'drop-in' planning permission.

“Whilst the judgment does not put the brakes on the use of drop-in permissions, it does raise a number of points that will necessitate particularities in terms of the structure and wording of drop-in permissions, as well as careful consideration by the decision maker in terms of the materiality of the changes proposed in the context of the underlying permission taken as a whole,” Lockerbie said.

“An already complicated corner of planning law just got even more complicated. To the extent there is an ‘easy’ answer to all of this I suggest it is one of legislative change. There is no logical reason that the provisions in the Town and Country Planning Act 1990 that relate to changes to planning permission should remain as inflexible as they currently are. The issues we currently face in terms of changes to planning permission and the use of drop-in permissions could all be swept away if the law could be changed to allow variations to planning permission of any scope/extent, subject of course to the usual decision-making considerations – i.e., against the development plan and any other relevant material considerations,” he said.

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