OUR VIEW OF THE LAND · GREY BELT
New research on grey belt appeals points to a promising route for some Green Belt land. The schemes that failed show why grey belt status is where the planning case begins, not where it ends.
Since December 2024, national planning policy has recognised some Green Belt land as grey belt, opening a route to development on sites that do not strongly contribute to three specified Green Belt purposes, subject to other policy requirements. Decisions on grey belt planning appeals now provide a growing body of evidence on how that route is working in practice.
Green Light for Grey Belt, prepared by Marrons on behalf of the Land, Planning and Development Federation (LPDF) and published in October 2026, reviews 355 appeal decisions referring to grey belt, issued between 12 December 2024 and 31 August 2026. Its headline finding is striking: of 38 major residential appeals, 30 succeeded.
A high success rate is a reason to examine a policy closely, however, not a percentage a landowner can apply to their own field. In our view, the more useful lesson lies in the eight major schemes that failed. They show that grey belt status can open a planning route, but a proposal still has to make the rest of its planning case.
Grey belt planning appeals: what the figures show
The research divides residential appeals by scale. Major schemes are those of ten or more homes, while minor schemes are those of one to nine.
| Residential appeals | Decided | Allowed | Share allowed |
| Major (10 or more homes) | 38 | 30 | 79% |
| Minor (1 to 9 homes) | 156 | 53 | 34% |
Source: Marrons on behalf of the LPDF, Green Light for Grey Belt (October 2026). The full study also covers non-residential appeals.
Major and minor schemes therefore recorded markedly different outcomes, and Marrons concludes that scale matters. The figures do not establish that a larger proposal would improve an individual site’s prospects: location, evidence, design and other differences may also influence the comparison.
The sample also calls for care. These are appeals, not every application made on grey belt grounds, and the major residential figures rest on 38 decisions. They describe how Inspectors treated the cases that reached appeal; they cannot predict the outcome for any particular site.
What the dismissed major residential appeals reveal
For understanding the limits of grey belt status, the eight dismissed major schemes are particularly instructive, because the report records why each one failed. At the time of decision, Inspectors found that four of the eight sites were not grey belt. In two, the land contributed strongly to checking the unrestricted sprawl of large built-up areas, which Marrons describes as generally the most contested Green Belt purpose. The other two failed a test, then part of the grey belt assessment, that excluded land where policies protecting areas or assets such as heritage and flood risk gave a strong reason for refusal.
That second test no longer applies. The revised National Planning Policy Framework (NPPF), published on 17 August 2026, removed it from the grey belt assessment, and Marrons therefore counts six of the eight sites as grey belt under the current Framework. On that basis, it concludes that “establishing that a site is grey belt is not the main challenge; it is the additional grey belt tests – alongside other matters – that have led to dismissals.” Our article on the 2026 NPPF changes for landowners covers the wider update.
A different classification would not, however, mean that either of the two affected proposals would now succeed. Heritage and flood risk remain planning considerations in their own right, and one of the two schemes also failed on sustainable location and the Golden Rules. Owners should therefore read every finding here alongside the Framework that applies when a new proposal comes forward.
Why grey belt status was not enough
The four sites that qualified as grey belt at the time still failed on other grounds. Across all eight appeals, four schemes fell short at least in part on the Golden Rules, two failed on whether development would undermine the remaining Green Belt, and two failed on sustainable location. Several appeals failed on more than one ground.
The clearest example comes from Sevenoaks. In an appeal for 39 homes, the Inspector found the site to be grey belt, appropriate in Green Belt terms and compliant with the Golden Rules, yet still dismissed the appeal on highways grounds. The site had cleared the grey belt questions; the wider planning case had not.
What landowners should investigate
For a landowner, the value of these decisions lies in the questions they raise. Taken together, they point to four areas worth investigating before assuming that grey belt policy creates an opportunity.
What supports the grey belt assessment?
Understanding what grey belt means for landowners starts with assessing how the land contributes to specific Green Belt purposes, judged on the site and its surroundings. Council studies may help, but in one dismissed case the Inspector gave limited weight to an assessment prepared before the grey belt concept existed.
Current, site-level evidence therefore matters. A strategic land promotion approach brings together site appraisal, planning strategy and the technical work needed to support a proposal.
Does the location support the proposal?
Sustainable location is a separate question from classification, and proximity to a settlement is not enough on its own. Marrons identifies walking and cycling connectivity as central to successful proposals.
What would a proposal need to provide?
The Golden Rules require policy-compliant affordable housing, necessary local or national infrastructure, and new or improved green space that the public can use. Half of the dismissed major schemes fell short on them at least in part, and Marrons advises treating them as part of the design process rather than resolving them later.
What could still decide the outcome?
Finally, grey belt policy does not displace the rest of the planning system. As the Sevenoaks case shows, matters such as highways, heritage or other site constraints can still determine an appeal once a proposal has answered the grey belt questions.
A route, not a verdict
The research points to a meaningful opportunity: 30 of the 38 major residential appeals in the study succeeded. The eight dismissals show why that opportunity still depends on more than grey belt status.
Our view is that the appeal evidence is a reason to assess Green Belt opportunities carefully, not to assume that grey belt status settles the planning case. Every site still has to make its own case on its own evidence.
Source: Marrons on behalf of the Land, Planning and Development Federation, Green Light for Grey Belt: Golden Opportunity, New Rules, and Still a Game Changer (October 2026).
Could grey belt policy be relevant to your land?
Whether land can benefit from grey belt policy depends on the site, the evidence and the wider planning case. If you own land in the Green Belt, Muller’s free, no-obligation land appraisal can give you an initial view of its development potential and the questions a proposal would need to address.
