Planning · England, with Wales noted

Green belt and grey belt

What can be built on green belt land under the December 2024 framework

What the green belt is

Green belt is not a landscape designation and says nothing about how attractive the land is. It is a planning policy whose one job, in the words of paragraph 142 of the National Planning Policy Framework, is “to prevent urban sprawl by keeping land permanently open”. Its essential characteristics are “openness and their permanence”. The policy is national but the boundaries are local: each council draws its green belt in its local plan, so whether a field is green belt is answered by a map, not by looking at the field.

The NPPF in force is the December 2024 revision, published on 12 December 2024 with technical corrections on 7 February 2025. Chapter 13, paragraphs 142 to 159, is the green belt chapter. Paragraph numbers below are from that version.

The five purposes

Paragraph 143 gives the green belt five purposes:

1. to check the unrestricted sprawl of large built-up areas
1. to prevent neighbouring towns merging into one another
1. to assist in safeguarding the countryside from encroachment
1. to preserve the setting and special character of historic towns
1. to assist in urban regeneration, by encouraging the recycling of derelict and other urban land

Purposes (a), (b) and (d) matter more than they did, because the grey belt definition turns on them.

Inappropriate development and very special circumstances

Paragraph 153 sets the presumption. Councils must give “substantial weight” to any harm to the green belt, including harm to openness. “Inappropriate development is, by definition, harmful to the Green Belt and should not be approved except in very special circumstances.” Very special circumstances do not exist unless the harm by reason of inappropriateness, and any other harm, “is clearly outweighed by other considerations”.

That is a high bar. Personal need, a shortage of housing in the village, a well designed scheme, an owner’s long connection with the land: individually these rarely amount to very special circumstances. A plot owner should assume that anything not on the exceptions list, and not grey belt, will be refused.

The exceptions

Paragraph 154 lists the buildings that are not inappropriate. For a house owner or self-builder the important ones are:

Exception	What paragraph 154 allows
(a)	Buildings for agriculture and forestry
(b)	Facilities for outdoor sport and recreation, cemeteries and allotments, so long as they preserve openness and do not conflict with the purposes
(c)	The extension or alteration of a building, provided it does not result in “disproportionate additions over and above the size of the original building”
(d)	The replacement of a building, provided the new building is in the same use and “not materially larger” than the one it replaces
(e)	Limited infilling in villages
(f)	Limited affordable housing for local community needs under development plan policies, including rural exception sites
(g)	Limited infilling or the partial or complete redevelopment of previously developed land, whether redundant or in continuing use (excluding temporary buildings), which would not cause “substantial harm to the openness” of the green belt

Paragraph 154(h) adds other forms of development that are not inappropriate provided they preserve openness and do not conflict with the purposes: mineral extraction, engineering operations, local transport infrastructure that can show a need for a green belt location, the re-use of buildings of permanent and substantial construction, material changes of use of land to outdoor sport, recreation or cemeteries, and Community Right to Build developments.

Three points follow for someone asking “can I build here”. First, an existing house in the green belt can usually be extended, but the NPPF glossary defines “original building” as the building as it existed on 1 July 1948 or, if built later, as it was built originally, so earlier extensions count against you; many local plans set a percentage of the original floor area [TO CONFIRM local figure]. Second, a house can be replaced with one that is not materially larger, compared with the existing building. Third, a permanent building can be re-used, which is why Class Q (see the Class Q page) sits comfortably with green belt policy. The previously developed land exception in (g) does not help with a farmyard: the glossary excludes from “previously developed land” any land that “is or was last occupied by agricultural or forestry buildings”, and residential gardens in built-up areas.

Grey belt

The December 2024 revision introduced grey belt. The glossary in Annex 2 defines it 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 paragraph 143. “Grey belt” excludes land where the application of the policies relating to the areas or assets in footnote 7 (other than Green Belt) would provide a strong reason for refusing or restricting development.

Footnote 7 lists the other protective designations: habitats sites and sites of special scientific interest, Local Green Space, National Landscapes, National Parks, the Broads, Heritage Coast, irreplaceable habitats, designated heritage assets, and areas at risk of flooding or coastal change. Land where those policies give a strong reason for refusal is not grey belt even if it fails to serve the green belt purposes.

Paragraph 155 then says that housing, travellers’ sites, or commercial and other development on grey belt is not inappropriate where all four of these apply:

1. the development would utilise grey belt land and would not fundamentally undermine the purposes (taken together) of the remaining green belt across the plan area
1. there is a demonstrable unmet need for the type of development proposed; for housing the footnote defines this as the council being unable to demonstrate a five year supply of deliverable sites with the applicable buffer, or having delivered less than 75 per cent of its housing requirement over the previous three years under the Housing Delivery Test
1. the development would be in a sustainable location, applying the sustainable transport policies of the NPPF
1. where applicable, the development meets the “golden rules” in paragraphs 156 to 157

The government’s planning practice guidance on green belt, updated on 27 February 2025, explains how to judge whether land “strongly contributes” to purposes (a), (b) and (d) (paragraph 005). For purpose (a), land contributes strongly where it is free of existing development, adjacent or near to a large built-up area, and lacks physical features nearby that could restrict and contain development. For (b), where it is free of development, forms a substantial part of a gap between towns, and development would be likely to cause loss of visual separation. For (d), where it is free of development, forms part of the setting of a historic town and makes a considerable contribution to its special character. Paragraph 009 says that in decision-making the council considers whether the site strongly contributes to purposes (a), (b) or (d) and whether development would fundamentally undermine the purposes of the remaining green belt. A field of scrub between a bypass and an industrial estate is a strong grey belt candidate. Open farmland on the edge of a town that stops it merging with the next one is not.

The golden rules

Paragraph 156 applies where a major housing development is proposed on land released from the green belt through plan preparation or review, or on sites in the green belt that are subject to a planning application. Major development for housing means 10 or more homes or a site of 0.5 hectares or more (NPPF glossary). The three golden rules are:

1. affordable housing, at the level set by the up-to-date development plan policy, or, until such a policy is in place, at the level in paragraph 157
1. necessary improvements to local or national infrastructure
1. the provision of new, or improvements to existing, green spaces that are accessible to the public, with new residents able to reach “good quality green spaces within a short walk of their home”

Paragraph 157 sets the interim affordable housing figure: 15 percentage points above the highest existing affordable housing requirement that would otherwise apply, subject to a cap of 50 per cent. Where there is no existing requirement, 50 per cent applies. The 50 per cent cap does not apply to rural exception sites, community-led exception sites, or where existing policy exceeds 50 per cent. Site-specific viability assessments are to follow the national guidance, and the viability guidance sets the benchmark land value approach for green belt release [TO CONFIRM the current premium figure]. Paragraph 158 says a development that complies with the golden rules “should be given significant weight in favour of the grant of permission”. Paragraph 159 sets the standards for the green space: it should contribute to the landscape setting, support nature recovery and meet local or national accessibility standards.

For a single self-build house none of this bites, because the golden rules attach to major development. For a landowner with a field, the rules mean that a grey belt release of 20 houses in an area with a 40 per cent affordable policy will carry a 50 per cent affordable requirement, and the price a housebuilder will pay for the land drops accordingly.

The sequential approach and local plan release

Green belt boundaries change only through the local plan. Paragraph 145 says they “should only be altered where exceptional circumstances are fully evidenced and justified, through the preparation or updating of plans”. Paragraph 146 says that exceptional circumstances include where a council cannot meet its identified need for homes, commercial or other development through other means, and that release should not fundamentally undermine the purposes of the remaining green belt taken together. Paragraph 147 requires the council to show it has examined all other reasonable options. Paragraph 148 sets the sequence: when release is necessary, plans should give priority to previously developed land, then grey belt, then other sustainable green belt locations. Paragraph 149 requires released boundaries to be capable of enduring beyond the plan period and to be drawn on clearly defined physical features, and allows “safeguarded land” to be identified between the urban edge and the green belt for the long term; safeguarded land is not for development now. Paragraph 150 says villages should be inside the green belt only where their openness needs protecting, and paragraph 151 asks councils to plan positively to enhance the beneficial use of green belt land.

An owner whose land sits on the urban edge of a council that is short of housing land should watch the local plan timetable and make representations at the call-for-sites stage; a site promoted as grey belt, with an assessment against purposes (a), (b) and (d), has a far better chance than one submitted as open countryside.

Wales

The NPPF does not apply in Wales. Planning Policy Wales, edition 12 (last updated July 2024), deals with green belts and green wedges together [TO CONFIRM paragraph numbers]. Green belts in Wales are designated through Strategic Development Plans at regional level and green wedges through local development plans, with green wedges reviewed at each plan review rather than treated as permanent [TO CONFIRM]. The presumption against inappropriate development and the list of acceptable development follow the English model, but there is no grey belt and there are no golden rules in Wales.

Checking a specific plot

The authoritative answer is the adopted local plan proposals map for the council area, which the council publishes online. The quickest national check is planning.data.gov.uk, the government’s planning data platform. Its green belt dataset holds the boundaries of land designated as green belt by local planning authorities, provided by MHCLG from annual snapshots submitted by councils in March and published in the autumn, currently 181 green belt areas, under the Open Government Licence. Open the map at https://www.planning.data.gov.uk/map?dataset=green-belt and zoom to the plot, or query https://www.planning.data.gov.uk/entity?dataset=green-belt with a point or polygon. Overlay the conservation area, listed building, National Landscape, flood zone and article 4 direction datasets on the same map to see whether the footnote 7 exclusions from grey belt apply.

Two cautions. The platform says its green belt data is partly created by MHCLG and is being replaced with data from authoritative sources, so treat a boundary that runs through a plot as a prompt to check the council’s own map. And a green belt boundary drawn along a hedge or road is precise to the width of a line; where a house sits on the boundary, the local plan policies map governs.

Sources

NPPF (December 2024, corrected 7 February 2025), chapter 13, paragraphs 142 to 159: https://www.gov.uk/guidance/national-planning-policy-framework/13-protecting-green-belt-land
NPPF Annex 2 glossary (grey belt, previously developed land, affordable housing, major development): https://www.gov.uk/guidance/national-planning-policy-framework/annex-2-glossary
NPPF publication page and change history: https://www.gov.uk/government/publications/national-planning-policy-framework–2
Planning practice guidance, Green Belt (updated 27 February 2025), paragraphs 005, 009 and 012: https://www.gov.uk/guidance/green-belt
Planning Policy Wales, edition 12: https://www.gov.wales/planning-policy-wales
planning.data.gov.uk green belt dataset: https://www.planning.data.gov.uk/dataset/green-belt