It is not uncommon for a development site to benefit from more than one planning permission, which can give rise to questions as to the extent to which the different developments can be carried out.
The Court of Appeal has recently grappled with this issue in the case of Hillside Parks Ltd v Snowdonia National Park Authority  EWCA Civ 1440 and has found in favour of the local authority so as to prevent a development authorised by a planning permission granted in 1967 being carried out on the basis that it was materially inconsistent with the development approved and carried out subsequently.
The case concerned a planning permission for a residential development of 401 dwellings. Following grant of the planning permission in 1967, the development progressed very slowly with a number of variations to the Master Plan, but in 1987 a judge granted a declaration that the development permitted by the 1967 permission had begun and that it could be lawfully completed at any time in the future. A number of planning permissions were granted subsequently, either as stand alone permissions or as variations to the 1967 permission. In 2017, the local planning authority contacted the appellant stating that, in its view, the 1967 permission could no longer be implemented because the developments carried out in accordance with the later planning permissions rendered it impossible to implement the original Master Plan.
The appellant sought to complete the remaining part of the development, relying on the declaration granted in 1987 and the case of F. Lucas & Sons Ltd v Dorking and Horley Rural District Council (1966) 17 P & CR 111 where it was held that, where on its true construction a planning permission authorised a number of independent acts of development, each such act would be lawfully carried out in accordance with the planning permission, regardless of whether any other such act was carried out at all or in accordance with the permission.
The High Court found for the local authority, concluding that, whilst the Court in the 1987 action had not erred in law in determining that the development could be completed pursuant to the 1967 permission, the development which had occurred since 1987 now rendered the development granted by the 1967 permission a physical impossibility. Thus, future development pursuant to the 1967 permission would no longer be lawful.
The Court of Appeal upheld this decision, saying that it was inconceivable that the Court in 1987 could possibly have intended that their declaration should continue to bind the parties regardless of future developments either as a matter of fact or in law. The Court referred to significant legal developments since that decision, and in particular the decision of the House of Lords in Sage v Secretary of State for the Environment, Transport and the Regions  UKHL 22. It was held in that case that a planning permission must be implemented “fully” and that a “holistic approach” must be taken. Therefore, for a development to be lawful, it must be carried out fully in accordance with any final permission under which it is done. That means that if a development for which permission has been granted cannot be completed because of the impact of other operations under another planning permission, that subsequent development as a whole will be unlawful.
The Court of Appeal concluded that it was no longer possible to implement the 1967 permission due to the factual developments since the judgment in 1987. The development which had taken place consisted not only of a different type of housing, with different alignment, but included the construction of roads on the estate which would be clearly incompatible with the road layout as depicted on the Master Plan, meaning that the High Court was entitled to reach the conclusion that it was now impossible for the 1967 permission to be implemented.
The Court of Appeal went on to say that, whilst it is conceivable that, on its proper construction, a particular planning permission does indeed grant permission for the development to take place in a series of independent acts, each of which is separately permitted by it, that is unlikely to be the correct construction of a typical modern planning permission for the development of a large estate such as a housing estate. Typically there would be not only many different residential units to be constructed in accordance with that scheme, there may well be other requirements concerning highways, landscaping, possibly even employment or educational uses, which are all stipulated as being an integral part of the overall scheme which is being permitted. The Court doubted, in those circumstances, that a developer could lawfully "pick and choose" different parts of the development to be implemented.
This case highlights that it is important to be cautious not to jeopardise one planning consent when carrying out development pursuant to another. If the implementation of one planning permission will prevent another development being carried out in its entirety, it could result in the loss of the benefit of that consent. Whilst it may be possible to structure a planning permission (or permissions) in such a way as to prevent that happening, a safer course of action may be to apply to amend a single consent, rather than to seek to rely on overlapping permissions.
For more information on the items raised in this article please contact Gemma Dudley on 01223 532747 or click here to email Gemma.