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Green Belt

Green Belt planning policy

The Labour Government reformed Green Belt policy in December 2024. Up until this point, the approach taken in the government’s national planning policies for England (NPPF) had remained broadly consistent since 2012. Planning policies adopted a protectionist approach (that is, generally restricting development on land designated as Green Belt).

In the December 2024 National Planning Policy Framework (NPPF) the government introduced the principle of ‘grey belt’ as a new land classification to take account of land which did not “strongly contribute” to certain Green Belt purposes. The framework also introduced ‘golden rules’ to secure affordable housing and infrastructure obligations for development proposed on Green Belt land.

The government states that the “fundamental aim” of the Green Belt “is to prevent urban sprawl by keeping land permanently open” around urban areas. This position has remained since the NPPF was introduced in 2012.

Local planning authorities (LPAs) are responsible for defining and maintaining Green Belt land in their local areas. Government planning policy on the Green Belt is set out in chapter 13 of the National Planning Policy Framework (NPPF, August 2026).

LPAs are required to prepare Green Belt assessments and identify grey belt land (this is land which meets the definition in the NPPF glossary). The assessment is also used to inform decisions on potential Green Belt boundary changes.

LPAs should set out Green Belt boundaries in their local plans. They can change the boundaries of Green Belt land in their area as part of the local plan review process. However, government guidance advises LPAs to only change Green Belt boundaries in “exceptional circumstances” where it is “evidenced and justified”. In certain cases, such as “the identification of suitable land around well-connected stations”, exceptional circumstances do not need to be demonstrated.

LPAs also decide planning applications on Green Belt land. Government guidance advises LPAs that, in general, development on the Green Belt is “inappropriate” and “harmful to the Green Belt”. It says that LPAs should allow development on the Green Belt only in “in very special circumstances” or where certain categories of development are “not inappropriate” on land designated as Green Belt.

Green Belt statistics

How large is the Green Belt?

Analysis in March 2023 shows England had around 16,384 km² (or 6,326 square miles) of Green Belt land, covering 12.6% of England’s land area.

The Green Belt is clustered around 15 urban cores; the largest are London (5,085 km²), Merseyside and Greater Manchester (2,477 km²) and South and West Yorkshire (including Sheffield, Leeds and Bradford, 2,465 km²).

How much building has there been on the Green Belt?

An estimated 93.1% of the green belt was undeveloped land in 2022. This land was primarily used for agriculture (65.0% of all green belt land). 6.8% of Green Belt land was developed, with over half of this developed land accounted for by roads and other transport infrastructure. Residential buildings accounted for 0.3% of Green Belt land.

From 2019-20 to 2021-22, 71.5 km² of previously undeveloped Green Belt land changed to a developed use, of which 7.6 km² turned into residential use.

How well is the Green Belt working?

In 2021 the Housing, Communities and Local Government Committee has noted that stakeholders are divided on whether the Green Belt should “never be built on” or constituted “an anti-growth mechanism” (PDF). Some commentators argue that Green Belt protections are too weak, and inappropriate development can encroach on the Green Belt. Others argue that the protections are too strong and that the Green Belt is a constraint on building enough homes.

Reaction to Green Belt reforms 

Green Belt reforms and the introduction of grey belt have generally been supported by the development industry with the Home Builders Federation (HBF) welcoming the changes. Urbanist architecture, a private sector practice, outlined the benefits of the reforms:

By designating underutilised or previously developed land that makes a limited contribution to Green Belt purposes, the policy directs growth to areas where it is most sustainable.

The Royal Town Planning Institute reported that challenges remain with the implementation of Green Belt policy reforms, highlighting the House of Lords Grey Belt Inquiry conclusions which “has cast doubt on whether this policy will make a meaningful difference”. In a recent planning conference Zack Simons KC emphasised the need for further clarity on grey belt policy.