Written by Nikki O’Hagan, 30th June 2026

Many landowners assume they cannot build on Green Belt land. It is true that this has traditionally been difficult, that development is still subject to greater constraints in the Green Belt than in many other locations, and that every prospective site should be assessed carefully before a decision is made to apply for planning permission. However, Green Belt policy has relaxed significantly in recent years.

One of the most important changes is that some Green Belt land on which residential development was previously resisted is now considered suitable for development. This is because national policy now specifically recognises and allows for the development of “grey belt” land. Grey belt is Green Belt land which is previously developed, or which is not performing a strong Green Belt function.

Alongside those policy changes, a recent High Court case has clarified another important point. Councils often object to Green Belt development on the basis that it would harm the “openness” of the Green Belt. However, in Mole Valley District Council v Secretary of State and Meloney [2025] EWHC 2127 (Admin), the Court confirmed that where development is “not inappropriate” in national policy terms, a council should not then treat that development as causing harm to Green Belt openness.

That is significant. It means that, in many Green Belt cases, the central question ought now to be whether the proposal is inappropriate development. If it is “not inappropriate”, a council should not be able to raise its effect on Green Belt openness as a separate objection.

This article explains what the Mole Valley case means, why it matters, and what owners should consider before applying to build on Green Belt land.

What is inappropriate development in the Green Belt?

For anyone hoping to build on Green Belt land, the first and most important question is whether the proposal is “inappropriate development”.

This phrase has a specific meaning in this context. National planning policy establishes that inappropriate development is, by definition, harmful to the Green Belt. It should not be approved except in very special circumstances. National policy also identifies certain types of development that are “not inappropriate” in the Green Belt. These include:

• Limited infilling in villages
• The residential or commercial development of grey belt land
• The proportionate extension or alteration of a building
• The replacement of a building with a building in the same use and not materially larger than the previous building.

The list above is a summary only. The full policy wording should always be checked in the National Planning Policy Framework before an application is prepared.

A proposal may appear to fall within one of these categories, but the policy tests usually require careful analysis. Terms such as “limited”, “infilling”, “proportionate” and “materially larger” require planning judgement and can be interpreted differently by applicants, councils, inspectors and courts. For example, when considering limited infilling in villages, the decision-maker may look at the spacing between existing buildings, the use and permanence of neighbouring buildings, and whether the scale, number and arrangement of the proposed dwellings would respond to the established pattern of development. A robust planning statement should therefore be provided with any application. This should explain and justify which “not inappropriate” category the proposal falls within, drawing on relevant case law where appropriate.

What is Green Belt openness?

Green Belt openness is one of the key concepts in Green Belt planning policy.

In simple terms, openness means the absence of built development. The fundamental aim of the Green Belt is to keep land permanently open and to prevent urban sprawl. This is why new development in the Green Belt is subject to additional constraints.

Openness is not the same as visibility. A development can affect openness even if it is partly screened, not prominent, or not visible in public views. The assessment is more about whether the proposal would make land feel more “built up”.

Councils have frequently cited openness concerns to resist even relatively modest additions to established sites. This has included garages and outbuildings within residential plots, as well as single-storey domestic extensions. New dwellings have usually faced even greater scrutiny. Any net increase in built form has often been treated as harmful to Green Belt openness.

Openness objections have been raised against proposals which are “not inappropriate” in Green Belt terms, not just against inappropriate development. This has resulted in the refusal of applications for proposals which were accepted to be “not inappropriate”.

The Mole Valley case is important because it clarifies whether that approach is correct.

What did the Mole Valley case decide?

The Mole Valley case deals directly with the relationship between “not inappropriate” development and Green Belt openness.

The case involved a proposal for a Gypsy and Traveller site in the Green Belt. The council had refused planning permission partly because of the effect of the development on Green Belt openness. However, the Planning Inspector allowed the appeal and granted permission. The Inspector found that the development was “not inappropriate” in the Green Belt. It should therefore not be treated as causing harm to Green Belt openness.

The council challenged that decision in the High Court. It argued that even if the development was “not inappropriate”, its effect on Green Belt openness still had to be assessed. It also argued that any harm to openness could still be taken into account in the decision. The Court rejected that argument.

The Court confirmed that development which is “not inappropriate” in the Green Belt should not be treated as harmful to Green Belt openness. That means a council cannot accept that a proposal is “not inappropriate”, but still refuse it on openness grounds.

For owners of Green Belt land, the decision removes a major obstacle that has previously frustrated many Green Belt proposals.

What does this mean for Green Belt landowners?

The combined effect of recent policy changes and the Mole Valley judgment is that Green Belt development opportunities are currently greater than they have been for many years.

This does not mean that every Green Belt site will be capable of development. Sites in open countryside are still likely to face significant resistance. So are sites which play an obvious role in separating settlements, or which have clear landscape, heritage or ecological sensitivity. Other planning issues, including access, highways, drainage, design, neighbouring amenity and local policy, will also remain relevant to all sites.

However, it does mean that landowners should consider having their land reviewed, even on an initial basis, before ruling out development. This applies both to sites which have never been assessed before and to sites which have previously been discounted, advised against, or refused planning permission on Green Belt grounds. Given the scale of recent change, many Green Belt sites which would not previously have received planning permission may now be suitable candidates for development. This is particularly true of previously developed land and infill village plots.

If you own a site in the Green Belt or are looking to build on Green Belt land, it is worth obtaining an up-to-date assessment before deciding whether to pursue a planning application. Planning Direct can carry out an initial review free of charge to identify whether there may be a realistic development opportunity. Where a site appears to have potential, we can also provide a more detailed planning assessment and, where appropriate, prepare a comprehensive planning application supported by detailed planning drawings and a robust planning statement.

Contact Planning Direct today to discuss you site.