Supreme Court to hear appeal in dispute over effect of implementing later planning permissions and 'drop in' amendments

The Supreme Court has agreed to hear a significant case in relation to the effect of implementing later planning permissions for the same site.

A panel comprising Lord Reed, Lord Leggatt and Lord Stephens granted Hillside Parks permission to appeal in part on 13 December, although their decision has only just been revealed in the Court's latest list of permission to appeal decisions.

Robin Green of Cornerstone Barristers, who represents the appellant, said: “On the Pilkington issue, the central question is: where there are successive planning permissions relating to the same site, and the later permission(s) is/are for focused localised changes (colloquially known as ‘drop in’ amendments) to a wider development approved in the original planning permission, is the effect of implementing the later permission(s):

(a) that the original planning permission becomes un-implementable only in relation to the areas affected by the later permission(s), or

(b) that the original permission becomes completely un-implementable including in relation to land outside, and unaffected by, the areas affected by the later permission(s)?”

The High Court considered that the answer was (b). This was upheld by the Court of Appeal in Hillside Parks Limited v Snowdonia National Park Authority [2020] EWCA Civ 1440.

The appellant submits that the answer is (a).

Green said this was “an issue of profound practical importance for the planning and development sector”.

The Supreme Court panel refused permission in relation to a ground relating to res judicata.

The case is due to be heard on 4 July 2022.

See also: One more time - multiple planning permissions - Mark Child analyses a recent Court of Appeal judgment involving a national park authority and what it means for sites with multiple planning permissions and the practice of ‘drop-in’ permissions. (15 January 2021)