Hillside Parks Ltd v Snowdonia National Park Authority

The Supreme Court held that the 1967 planning permission for the Balkan Hill site (the "Master Plan") cannot be further implemented because later, post-1987, developments carried out under independent permissions have materially departed from and made it physically impossible to implement the 1967 scheme. The court applied the Pilkington principle that an unimplemented permission is rendered unenforceable only if physical changes to the land make implementation of that permission impossible. The court rejected the appellant’s submission that planning permissions can be extinguished by a doctrine of abandonment (endorsing Pioneer Aggregates) and rejected the proposition that multi-unit permissions are generally severable so as to authorise independent parts of a larger scheme absent clear indication. The court also held that the appellant had not proved that the post-1987 permissions should be construed as variations of the 1967 permission; on the material before the court those permissions were independent and their implementation made compliance with the Master Plan impossible.

Background and parties: The dispute concerned the Balkan Hill site near Aberdyfi, subject to a 1967 full planning permission for 401 dwellings shown on a Master Plan. The appellant (site owner/developer) had built a small number of houses over decades, often under separate subsequent permissions; the respondent is the Snowdonia National Park Authority (local planning authority).

Procedural history: Drake J (unreported, 9 July 1987) had earlier held that the 1967 permission had been lawfully begun and could be completed. Subsequent developments and permissions since 1987 led the developer to seek declarations in 2017 that the Authority was bound by Drake J’s findings and that the 1967 permission remained implementable. HHJ Keyser QC dismissed the claim ([2019] EWHC 2587 (QB)); the Court of Appeal dismissed the appeal ([2020] EWCA Civ 1440). The Supreme Court allowed permission to appeal on the specific issue of whether further development may lawfully be carried out under the 1967 permission.

Nature of the claim / relief sought: Declarations that (i) the Authority was bound by Drake J’s 1987 judgment and (ii) the 1967 permission remained valid and could be completed.

Issues before the Supreme Court:

• whether the Pilkington principle should be treated as a doctrine of abandonment or as a test of physical impossibility;
• whether the 1967 permission for a multi-unit development could be severed so as to allow construction of remaining units where other incompatible development had taken place;
• whether the post-1987 permissions should be construed as variations of the 1967 permission (so preserving the 1967 permission in modified form) or as independent permissions that made implementation of the Master Plan impossible;
• whether departures from a permission must be material to have the effect of preventing further implementation.

Reasoning and holdings on the issues: The court (Lord Sales and Lord Leggatt, with agreement) analysed the authorities and planning statute. It affirmed that Pilkington is best understood as a test of physical impossibility (not abandonment) and that Pioneer Aggregates precludes a doctrine of abandonment in planning law. The court rejected the Lucas decision as wrongly decided to the extent it treated a multi-unit permission as generally severable into freely combinable unit permissions. It held that multi-unit permissions are normally to be read as an integrated whole absent clear indication otherwise, and that a departure prevents further implementation only if material in the context of the scheme as a whole. The court found that the appellant had not adduced the underlying applications and plans for the post-1987 permissions and had not shown they were intended to operate as site-wide variations; on the material available the post-1987 developments were independent and materially inconsistent with the Master Plan, making further implementation of the 1967 permission physically impossible. The court dismissed the appeal.

Wider context noted: The court emphasised the statutory nature of planning control and the limited powers to vary permissions, and that a pragmatic difficulty for developers in seeking local departures does not justify judicially importing doctrines (such as abandonment) inconsistent with the statutory code.

Appeal dismissed. The court held that the Pilkington principle is a test of physical impossibility (not abandonment); multi-unit permissions are generally to be read as an integrated whole unless clearly indicated otherwise; departures bar further implementation only if material; the appellant failed to show post-1987 permissions were genuine variations of the 1967 permission and those later developments made implementation of the Master Plan physically impossible.

Appeal from the Court of Appeal [2020] EWCA Civ 1440, which dismissed the developer's appeal from the High Court decision of HHJ Keyser QC ([2019] EWHC 2587 (QB)) that had refused the declarations sought. Earlier factual/ legal determination by Drake J (unreported, 9 July 1987) that the 1967 permission had been begun.