Property Week quotes Claire Fallows on the Hillside Parks vs Snowdonia National Park Authority judgment two years on

When the Supreme Court rejected Hillside Parks’ appeal to build out parts of a masterplan for the Welsh seaside resort of Aberdovey submitted more than 50 years earlier, the ruling told the property industry that two planning applications cannot both be valid at once.

It also reaffirmed the Pilkington principle. Established in 1973, the principle means a development cannot legally proceed under existing planning permission if a new, incompatible planning permission has been granted and implemented on the same site.

The case highlighted a problem that can arise with modern, complex developments spread over many phases, on which planning permissions are almost always amended. This used to be done via a Section 73 ‘drop-in’ application. In Hillside, the Supreme Court reaffirmed that when a drop-in application is submitted, the original planning consent is thus invalid.

In its article on the implications of the ruling two years on, Property Week explains that the court’s judgment was a "rude awakening" for the industry and explores the question: After two years, has the property profession gotten to grips with the ruling?

Claire Fallows, Partner and Head of Planning, was interviewed for the piece and explains that the process for ensuring developments tick all the legal boxes has become more convoluted:

Developers are facing more detailed legal drafting requirements [...] For multi-phase projects, every phase needs to be insulated from legal risks due to Hillside. The industry now has to balance adaptability with rigorous documentation, a shift that affects both planning flexibility and project timelines.

"One clear result of Hillside is the industry’s push for indemnity insurance on large projects. While helpful, insurance isn’t a substitute for legislative clarity. Developers want to see legal reforms that account for the realities of phased developments and mitigate risks from overlapping consents.

Claire goes on to explain that the Section 73b process – meant for changes that are not “substantially different” – may not go far enough, and argues that broader reforms may be needed.

Read the full article here (subscription required).