Hillside Parks: Supreme Court unanimously reaffirms Pilkington principle

The Supreme Court has today unanimously dismissed the developer’s appeal in the long-running Hillside Parks dispute about whether a 55-year old planning permission to build 401 homes in Aberdyfi, north Wales, can still be relied upon. Giving the judgment of the court, Lord Sales and Lord Leggatt (with whom Lord Reed, Lord Briggs and Lady Rose agreed) concluded that both the Court of Appeal and the High Court had correctly interpreted the historical planning permission in the case as a permission to carry out a single scheme of housing development. The Supreme Court rejected the developer’s contention that the permission should be interpreted as separately authorizing clusters of housing within the site, some of which could still be built alongside the 41 houses erected on the site to date pursuant to subsequent planning permissions. Their Lordships agreed with the local planning authority, the Snowdonia National Park Authority, that the houses and estate roads built on the site to date are inconsistent with the historical planning permission. As a result, it is now physically impossible to develop the site in accordance with that permission. In coming to this conclusion, the Supreme Court unanimously reaffirmed the Pilkington principle of physical impossibility in planning law, stressing that “the test of physical impossibility applies to the whole site covered by the unimplemented planning permission, and not just the part of the site on which the landowner now wishes to build”: [41]. Going further than the courts below, their Lordships also considered it “clear” that the anomalous judgment in F Lucas & Sons Ltd v Dorking and Horley Rural DC (1964) 17 P & CR 116, on which the developer relied, was “wrongly decided”: [49]. In Lucas, the court had interpreted a planning permission to build 14 houses as severable into discrete permissions for each individual house, observing that not interpreting the permission in that way could make the owner of each house vulnerable to enforcement action if the entire scheme were not completed. The Supreme Court rejected that concern:

“55. The analytical error made in the Lucas case was to fail to distinguish between two significantly different propositions. The first is that, from a spatial point of view, a planning permission to develop a plot of land is not severable into separate permissions applicable to discrete parts of the site. The second is that, from a temporal point of view, development authorised by a planning permission is only authorised if the whole of the development is carried out. The rejection of the second proposition does not undermine the first.”