The Supreme Court’s judgment in Hillside Parks Ltd v Snowdonia National Park Authority  UKSC 30 has been eagerly awaited, given the importance for dealing with overlapping planning permissions.
The case concerns the relationship between, and the effects of implementing, successive grants of planning permission on the same land. The Court of Appeal judgment, which we reported on, led to wariness and ambiguity about the implications for sites with multiple permissions and the practice of ‘drop-in’ permissions.
The authority granted permission for 401 homes in 1967 (“the 1967 Permission”), detailing the proposed location of each house and the road layout. A series of additional planning permissions were granted, each of which departed from the scheme of development authorised by the 1967 Permission. In 1987 the High Court issued a declaration that the development authorised by the 1967 Permission could still lawfully be completed at any time in the future.
Following that declaration eight further planning permissions were granted – all of which departed from the 1967 Permission. Only 41 homes had been constructed in progress described as “glacial”. Most of the consented homes could still be constructed in accordance with the 1967 masterplan, but some of the 41 homes had been constructed on land proposed for roads and vice versa, such that it became physically impossible for the whole development authorised by 1967 Permission to be built out fully in accordance with that permission.
The Court of Appeal upheld the High Court’s finding that it had become impossible, due to the events since 1987, for the 1967 Permission to be implemented in full (and, therefore, any further at all). The appeal to the Supreme Court was specifically on the question of whether any further development may be lawfully carried out under the 1967 Permission.
Endorses the Pilkington principle: Where, as a result of physical alteration of the land under one permission, it becomes physically impossible to carry out development authorised by an earlier permission, that earlier permission can no longer be relied on. Lord Sales and Lord Leggatt (giving the leading judgment) stated: “where the test of physical impossibility is met, the reason why further development carried out in reliance on the permission is unlawful is simply that the development is not authorised by the terms of the permission, with the result that it does not comply with section 57(1) [TCPA 1990]”.
Putting parameters around this, the Supreme Court held:
- That “mere incompatibility” with the terms of an earlier consent (for example a breach of planning condition) is not fatal to reliance on that earlier permission. What matters is whether it is physically possible to carry out the development authorised by the terms of the unimplemented permission. That is a factual question which depends on (i) the terms of the unimplemented permission and (ii) what works have already been done.
- It is only where there are “material departures” that a developer would be unable to rely on an existing permission.
Severability is a matter of interpretation: Multi-unit development consents should not be construed as permitting a series of independent and severable permissions to construct individual elements of the scheme unless there is an express indication to the contrary.
Developments do not have to be completed in full to be lawful: The Supreme Court judgment confirms that when permission is granted for a multi-unit development:
- that permission authorises each stage of that development for so long as it remains physically possible for the whole development to be constructed; and
- there is nothing in statute requiring the scheme to be completed in full and failure to do so does not render what has been built unlawful.
This is welcome clarity (and comfort) following the Court of Appeal’s suggestion that in order for development to be lawful, a planning permission must be implemented “fully'”.
What are the practical implications?
The key questions when looking at a ‘drop-in’ application are whether:
- The ‘drop-in’ will, when works are carried out, make it physically impossible to complete the original permitted development. Only if so will the ‘drop-in’ works cause the original permission to fall away.
- The original consent has been expressly structured and worded to allow for that. That can be addressed with relative ease on a new application but is more challenging to retrofit on an existing consent where amendments to the description of development can only be amended via section 96A (with Finney confirming that a section 73 permission cannot alter the description of development).
- If (2) does not apply, can a modified permission for the whole site be secured (either via section 73 or a new consent) which wraps up the original planning permission together with necessary modifications? The judgment indicates [84, 91] that updating the original application documents to show the integrated whole may do the job. The volume of supporting material and scale of updates likely to be needed in most cases where ‘drops-in’ are contemplated may be challenging.
‘Drop-ins’ should still remain an option provided that the framework of the existing consent is appropriately structured and worded.
Two final words of caution: Firstly, the Supreme Court emphasised that this case concerned grants of full planning permission and seemed to suggest that detailed plans submitted with full applications “have particular significance”. The implications for ‘drop-ins’ on outline or hybrid applications remains unclear. Secondly, the judgment refers repeatedly to looking at whether it is physically possible to implement the existing consent by reference to works already carried out. That will need to be understood by investors and developers acquiring, selling and funding development parcels.
 Pilkington v Secretary of State for the Environment  1 WLR 1527
 F Lucas & Sons Ltd v Dorking and Horley Rural District Council (1964) 17 P&CR 116 being held to have been wrongly decided, on the facts.