Irwin Mitchell’s Planning & Environment Blog
Welcome to our monthly blog series from the Planning & Environment team at Irwin Mitchell.
Each month, we will be bringing together the latest articles written by our team covering key developments, legal insights, and practical guidance across the planning and environmental law landscape. Whether it's new legislation, landmark cases, or upcoming policy changes, our aim is to keep you informed about what is happening in the planning and environmental world.
In this edition, we are highlighting the articles we have published during September. We hope you find them insightful and useful in your work.
Explore the highlights below:
Flood risk PPG update: Sequential test clarified
By Stefano DAmbrosio Nunez
Published 30 Sept 2025
Just like water, planning policy rarely stands still and the September 2025 update to the Planning Practice Guidance (PPG) on flood risk is a prime example. Building on the December 2024 NPPF revision and the Court of Appeal’s decision in Mead Realisations Ltd v Secretary of State, the update brings a more pragmatic approach to the Sequential Test, which has often been criticised for being overly rigid and unclear. The update addresses how the sequential test should be applied around, what counts as a “reasonably available” site, how to identify the “area of search,” and when a site-specific Flood Risk Assessment might make a sequential test unnecessary.
Failure to publish background papers leads to quashing of planning permission
By Sadiah Geloo and Stefano DAmbrosio Nunez
Published 30 Sept 2025
In the recent High Court ruling R (Wild Justice) v Pembrokeshire Coast National Park Authority planning permission was quashed after the Local Planning Authority failed to publish background papers that were materially relied upon in the Officer’s Report, breaching Section 100D of the Local Government Act 1972. The court found that the omission of the NRW Draft Report caused material prejudice to the claimant, while other documents were not considered background papers. The judgment serves as a reminder to Local Planning Authorities to follow requirements under Section 100D of the Local Government Act 1972 and publish all documents that are materially relied upon Officer’s Report before granting planning permission
By Anna Tranter
Published 18 Sept 2025
In a recent judgment reaffirming planning law principles in relation to Green Belt development policy and site deliverability, the High Court dismissed a challenge to a decision granting retrospective permission for a material change of use from rural land to residential and touring caravans on Green Belt land. The Court dismissed the argument that openness should still be considered even where development is deemed “not inappropriate” under the updated NPPF. This reaffirmed the Lee Valley precedent, as applying openness tests in such cases would undermine the purpose of the new grey belt exception, which is intended to allow certain developments that were previously restricted. The judgment also reaffirmed that while planning permission is not itself a pre-requisite for site deliverability, it is an element to consider in respect of whether there is a realistic prospect of development. Lastly, the court emphasised the principle that in adversarial hearings it is for the parties to present the evidence and their best case at the appeal.
Planning permission quashed after failure to publish Section 106 agreement
By Chyna Fairclough-Jones
Published 17 Sept 2025
In Chidswell Action Group v Kirklees Council, a planning permission was quashed due to the Local Planning Authority’s failure to publish the draft Section 106 agreement prior to issuing the decision notice. This was held to have deprived objectors of the opportunity to comment on key issues in breach of Article 40(3)(b) of the Town and Country Planning (Development Management Procedure) Order 2015, an omission which on the facts could have materially influenced the decision. This follows a similar ruling by the Court of Appeal in Greenfields v Isle of Wight Council, reinforcing that late or withheld publication of Section 106 agreements may expose decisions to legal challenge and delay.
