Development in the “grey belt” is becoming an increasingly popular option for developers and landowners, with a recent appeal decision secured by Thrings offering timely guidance in this emerging policy space.
Fred Quartermain, Partner in Thrings’ Planning and Environment team who led the successful legal argument that won the appeal, takes a look at the case and what developers can learn from its outcome.
What is the “grey belt”?
The planning system is no stranger to evolving policy shifts, and few have generated as much interest in recent months as the introduction of the grey belt.
Formally introduced as part of the Labour government’s raft of updates to the National Planning Policy Framework (NPPF) in December 2024, grey belt enables new opportunities for sustainable development on suitable sites without undermining the core objects of the Green Belt.
Under the NPPF, land that fails to strongly serve these purposes – namely checking unrestricted sprawl, preventing the merging of neighbouring towns and preserving the setting and special character of historic towns – may be reclassified as grey belt.
The Thundersley appeal – what happened?
Plans for a new development of up to 47 dwellings in Thundersley, Essex, were submitted by Foxberry Developments to Castle Point Borough Council in June 2024 but, despite support from offices, the application was refused on the grounds that it would be inappropriate development in the Green Belt, resulting in an appeal to the Planning Inspectorate.
In considering the appeal, the Inspector considered the key issues to be:
- Biodiversity and protected species – The site formed part of a Local Wildlife Site. Surveys identified potential habitats for bats and badgers. The Inspector accepted that a suite of mitigation measures (including a Landscape and Ecology Management Plan, badger method statement, wildlife-friendly lighting, and green corridors) could address ecological impacts.
- European sites – The site lay within the Zone of Influence of the Essex Estuaries SAC and SPAs. Through a Section 106 agreement, the developer committed to contributions under the Essex Coast RAMS strategy, satisfying legal tests for mitigation.
- Grey belt and Green Belt policy – The crux of the case lay here. The Inspector found the site was enclosed on three sides by housing, with further development under construction nearby. Its contribution to preventing sprawl or town-merging was therefore “weak,” and it did not affect historic towns. On this basis, it was grey belt land.
The appeal then turned to the NPPF’s tests for grey belt development, which found that development would not undermine the remaining Green Belt purposes given the site’s context and isolation from open countryside, as well as its close proximity to services and bus routes.
It was also identified that there was unmet housing need as the Council could not demonstrate a five-year housing land supply, and that the plans would enhance the community with the Section 106 agreement securing 50% affordable housing, education and healthcare contributions, and publicly accessible open space.
These outcomes secured approval for the appeal and planning permission granted for the scheme as it was not inappropriate development in the Green Belt – a decisive shift from the “very special circumstances” test that applied before the introduction of grey belt policy.
What can be learned from this appeal
This decision offers several valuable takeaways:
- Evidence is vital – Foxberry’s success hinged on robust ecological surveys, a clear drainage strategy, and detailed mitigation proposals. Developers should be ready to supply up-to-date technical evidence to reassure both councils and Inspectors. This means understanding whether your land makes only a weak contribution to Green Belt purposes, and how this can be evidenced - Badgers, bats, drainage, and transport are recurring pinch points so address these with credible reports from the outset.
- Section 106 obligations are pivotal – Affordable housing and infrastructure contributions need to be locked into legal agreements, with Foxberry’s willingness to commit to this through a well-structured Section 106 central to the positive outcome. Be sure to incorporate affordable housing, open space, and infrastructure contributions into your scheme design and viability assessments from day one.
- Location within the grey belt is not enough – Being in the grey belt does not guarantee approval. Applicants must still show unmet housing need, sustainability, and compliance with policy tests. Where councils lack a five-year supply, the argument for development strengthens.
- Local Plan context matters – Although Castle Point had withdrawn its emerging Local Plan, the Inspector gave significant weight to the previous examining Inspector’s conclusion that this site was suitable for housing. Developers should always examine how their site has featured in past Local Plan evidence.
- Community objections can be managed with evidence – Local residents raised concerns over wildlife, highways and flood risk. These were carefully addressed with expert evidence and conditions, neutralising them as reasons for refusal.
- Expert planning and legal advice will give you a better chance of success – The grey belt is new territory. Ensuring your application is aligned with national policy and supported by watertight planning obligations will be crucial.
Fred Quartermain, Partner in Thrings’ Planning and Environment team, said: “We are pleased to have supported Foxberry Developments in securing this appeal decision, which demonstrates that grey belt policy is more than theory – it’s already reshaping how development opportunities are assessed in Green Belt areas.
“For landowners and developers, the message is clear: with the right evidence, planning obligations, and site context, grey belt sites can now unlock real potential for housing delivery.”
Thrings’ Planning and Environment lawyers have extensive experience in navigating complex local and national planning policy legislation and has successfully supported commercial and residential applications through the approval and appeal processes. To find out more and for advice on your development proposals, please do get in touch.
