Grey Belt in the NPPF: What December 2024 Actually Changed

The December 2024 National Planning Policy Framework introduced "grey belt" into planning policy for the first time. After months of political discussion, the concept now has a formal definition and a policy framework. But the reality of what changed is more nuanced than either the celebratory or the alarmed headlines suggested.

This article explains what the December 2024 NPPF actually said about grey belt, how the August 2026 Framework, published on 17 August 2026, now sets it out, how it interacts with the broader Green Belt framework, and what it means in practice for landowners, developers, and local authorities.

Grey belt is defined in the NPPF glossary, introduced in December 2024 and now at Annex B of the August 2026 Framework, as land in the Green Belt comprising previously developed land and/or any other land that, in either case, does not strongly contribute to any of purposes (a), (b), or (d) in policy GB2. The purposes of Green Belt are well established, and policy GB2(1) lists all five: checking urban sprawl, preventing neighbouring towns from merging, safeguarding the countryside from encroachment, preserving the setting of historic towns, and assisting in urban regeneration. Only the first, second, and fourth count towards grey belt.

The key words are "and/or" and "in either case". Grey belt land can be previously developed land (brownfield in the Green Belt) or other land, but in both cases it must not strongly contribute to purposes (a), (b), or (d). The second category is the significant one, because it opens up the possibility of development on greenfield land within the Green Belt that is assessed as making a limited contribution to those purposes.

Grey belt works through two routes, both introduced in December 2024 and carried into the August 2026 Framework. For plan-making, policy GB4(1)(d)(i) gives priority, when Green Belt boundaries are altered, to the release of previously developed land within the Green Belt, then to grey belt land which is not previously developed, and then other Green Belt locations, so long as this promotes a sustainable pattern of development overall. For decisions, policy GB7(1)(g) makes development on grey belt land not inappropriate in the Green Belt where all of its conditions are met.

It is important to be clear about what grey belt does not do:

Grey belt does not remove land from the Green Belt. Land identified as grey belt remains in the Green Belt until it is formally released through the Local Plan process, and Green Belt policy continues to apply to it. What grey belt changes is the decision route: under policy GB7(1)(g), development on grey belt land is not inappropriate where all four of its conditions are met, and it then does not need to demonstrate very special circumstances. A proposal that fails any one of them is inappropriate development, unless it falls within another policy GB7 category such as the redevelopment of previously developed land under GB7(1)(e), and then needs very special circumstances under policy GB6(2).

Grey belt does not create an automatic right to develop. Grey belt status identifies land that should be prioritised if Green Belt boundaries are altered, and release must happen through the plan-making process with proper consultation, sustainability appraisal, and examination. To use the grey belt route, a planning application on land that stays in the Green Belt must meet every condition in policy GB7(1)(g), including an evidenced unmet need and, for major housing, the golden rules in policy GB8.

Grey belt does not override other planning constraints. Land may be grey belt and also affected by flood risk, heritage, ecology, or landscape constraints. Those constraints must still be assessed and addressed through the normal planning process. The December 2024 definition excluded land where policies such as those for designated heritage assets or areas at risk of flooding would provide a strong reason for refusing or restricting development. The August 2026 definition drops that exclusion, so those constraints are now weighed when the proposal is decided rather than when the land is classified.

The December 2024 NPPF also made significant changes to paragraph 11 of that edition, the tilted balance. Where a local authority could not demonstrate a sufficient supply of housing land, the presumption in favour of sustainable development applied, and permission was to be granted unless the adverse impacts would significantly and demonstrably outweigh the benefits. The August 2026 Framework replaced that mechanism. Policy S3 applies the presumption through policy S4 within settlements and policy S5 outside them, and policy S5(5) routes Green Belt proposals to policies GB6, GB7, and GB8 instead, while directing that development which is not inappropriate under policy GB7 should be approved unless the benefits would be substantially outweighed by any adverse effects, assessed against the national decision-making policies in the Framework.

The interaction between grey belt and housing supply is where the real impact lies. For housing, the evidenced unmet need that policy GB7(1)(g)(ii) requires means, under footnote 41, the lack of a five-year supply of deliverable housing sites, including the relevant buffer, or a Housing Delivery Test result below 75% of the housing requirement over the previous three years. For local authorities in that position that have not engaged with Green Belt review through their Local Plan, the pressure to consider grey belt release is significant. The government's intention is clear: housing delivery should not be constrained by Green Belt land that is not strongly performing its Green Belt function.

The December 2024 NPPF also revised the standard method for calculating local housing need. The revised method produces higher housing figures for many authorities, particularly those in high-demand areas. This increases the gap between housing need and supply, which in turn increases the number of authorities that cannot demonstrate a five-year supply. Under the December 2024 Framework that triggered the tilted balance; in the Green Belt it now supplies the evidenced unmet need that the grey belt route requires.

The combined effect of higher housing numbers, the housing supply tests, and the grey belt framework creates a coherent (if politically contentious) policy direction: local authorities must plan for more housing, and if they do not, the framework provides mechanisms (including grey belt release) to deliver it.

The December 2024 NPPF did not prescribe a methodology for assessing whether land strongly contributes to Green Belt purposes. The August 2026 Framework does. Annex E sets out the process for Green Belt assessments, and policy GB2(3) says local plan preparation should be informed by an assessment conducted in accordance with it which identifies grey belt. Annex E is written for that plan-making assessment, and whether an applicant must follow it on a planning application is not settled on the face of the text, so following it is the prudent course.

Annex E follows the established Green Belt assessment methodology: it grades each assessment area as making a Strong, Moderate, or Weak or None contribution to purposes (a), (b), and (d), with illustrative features for each grade. Land that does not contribute strongly to any of the three is grey belt under the Annex B definition. Annex E also narrows the purposes: villages are not large built-up areas for purpose (a), purpose (b) concerns the merging of towns (including cities), not villages, and purpose (d) concerns historic towns, not villages.

Our analysis of existing Green Belt reviews across England shows that many authorities have already identified parcels of Green Belt land that make a limited contribution to Green Belt purposes. These existing assessments provide a starting evidence base for identifying grey belt land, although they need checking against the Annex E criteria.

For landowners with land in the Green Belt, the grey belt framework creates a new pathway, but not a shortcut. The key questions are:

Is the land previously developed? If so, and it does not strongly contribute to purposes (a), (b), or (d), it is grey belt. Previously developed land is first in line for release under policy GB4(1)(d)(i), so long as this promotes a sustainable pattern of development overall, and its redevelopment can also be acceptable on a planning application under policy GB7(1)(e) where it would not cause substantial harm to the openness of the Green Belt.

Does the land strongly contribute to Green Belt purposes? If not, it may qualify as grey belt. This assessment requires professional judgement and evidence, typically a Green Belt purpose assessment against purposes (a), (b), and (d) in policy GB2, following the Annex E criteria.

Is the local authority reviewing its Local Plan? Release from the Green Belt happens through the plan-making process. If the authority is in the early stages of a Local Plan review, there may be an opportunity to promote grey belt land for allocation. Outside that process, a planning application can use policy GB7(1)(g) where all four of its conditions are met.

Can the development deliver the golden rules? NPPF policy GB8 sets three golden rules for major housing development on Green Belt land, including grey belt: until the local plan sets a Green Belt-specific requirement, affordable housing at 15 percentage points above the highest existing requirement, capped at a maximum of 50%; necessary improvements to local or national infrastructure; and new or improved green space accessible to the public. These requirements are higher than typical policy requirements and must be factored into viability assessments, and policy GB8(3) allows a viability case against them in three circumstances only. The earlier draft Working Paper proposed a flat 50% affordable housing rule; the December 2024 NPPF replaced that with the +15 percentage points formula, which the August 2026 Framework keeps.

In the months since December 2024, several local authorities have begun incorporating grey belt assessments into their emerging Local Plans. Some authorities that had stalled their Green Belt reviews have restarted them. A small number of appeal decisions have begun to reference grey belt in their reasoning, although the case law is still in its infancy.

The practical impact will depend on how quickly authorities adopt the framework, how robustly they assess Green Belt performance, and whether the "golden rules" for grey belt development prove deliverable in viability terms. The affordable housing requirement (+15 percentage points above the local target, capped at 50%) will be tested against viability only where one of the three circumstances in policy GB8(3) applies.

Grey belt is a meaningful policy change, but it is evolutionary rather than revolutionary. It formalises an approach that many authorities were already taking through Green Belt reviews and provides a policy hook for prioritising the release of poorly performing Green Belt land.

For developers and landowners, the key message is that grey belt creates an opportunity through two routes, the plan-making process and, where every condition in policy GB7(1)(g) is met, a planning application. It is not a bypass around Green Belt policy. The sites that will benefit most are previously developed sites in the Green Belt and greenfield sites that demonstrably do not serve purposes (a), (b), or (d), where there is an evidenced unmet need or a willing local authority engaging with its Local Plan.

Understanding the new framework (and being able to demonstrate where land sits within it) is now an essential part of land promotion in Green Belt areas.