Updated 20 September 2026
Green Belt
Green Belt wraps the towns of Hertfordshire and western Essex, and previously developed land inside it is not open housing stock. But the towns are inset — cut out of the belt — and that is where almost all the region's leftover land sits. Tested against the government's Green Belt polygons, only a small share of East of England register sites fall inside the boundary. This page used to say otherwise.
A correction, first
Until 20 September 2026 this site tagged every register point in a Green Belt authority as Green Belt, and this page described that as one of the larger discounts on leftover land. That was wrong, and the error ran in the same direction as the argument, which is the kind worth naming.
Checking each point against the national Green Belt polygons instead of its council's name cut the tagged capacity by roughly nine tenths. The reason is simple once stated: the Metropolitan Green Belt surrounds towns, it does not cover them. Borehamwood, Watford, Hemel Hempstead, St Albans and Harlow are inset — deliberately cut out of the belt — and that is precisely where a brownfield register finds its sites. One site this page's map used to offer as a Green Belt example was a fire station and job centre in the middle of Borehamwood, several hundred metres inside the inset boundary.
The step now uses the boundary. It produces a much smaller discount, and that is the honest number.
Where it sits
The metropolitan Green Belt covers most of Hertfordshire and laps into Essex. Broxbourne, Hertsmere, Three Rivers, St Albans, Welwyn Hatfield, Epping Forest and Brentwood are not short of countryside. They are short of urban land that is already developed and free of Green Belt purposes.
A brownfield register in those districts is mostly town-centre leftovers, hospital or campus land, and a small number of genuinely Green Belt sites: a health club on a village edge, a farmstead, a works on a lane between two towns. It is not a hidden city, and it is not a large Green Belt problem either.
Why it is still a discount
- Green Belt policy still applies to previously developed land. Being a former building is not a permission.
- The "brownfield" Green Belt plots that do exist are usually still performing a Green Belt purpose: gaps between towns, the setting of a historic town, or countryside in active use.
- Releasing them does not create the continuous urban land that density uplift needs.
- It is a small discount applied late in the walk, after the larger ones. Most Green Belt register sites have already dropped out for want of permission, or for flood, ground or ownership reasons, before this step runs.
The government's own brownfield passport paper said there are not enough register sites to deliver the homes the country needs. Grey belt does not reverse that finding for the East. It relocates the argument to the Green Belt edge.
How to read the map
The Green Belt step takes out register points that fall inside a Green Belt polygon in the national dataset, tested one point at a time. A site in a Green Belt authority whose point sits in an inset town is not lit, because it is not in the Green Belt.
Two caveats. The register publishes a point, not a boundary, so a large site whose point sits just outside the line may still have Green Belt land within it. And boundaries change with local plans. For a named plot, the authority's own proposals map is the test.
Questions people ask
- Is Green Belt brownfield automatically developable?
- No. Previously developed land in the Green Belt can be reused in limited cases. The land still has to pass Green Belt policy, and much of it remains in active use.
- What about grey belt?
- The 2024 working paper introduced grey belt as Green Belt that is already developed or that does not strongly serve the stated Green Belt purposes. It is not a new register of housing land, and it does not enlarge the East's urban brownfield stock.
Where the numbers come from
- Green belt dataset — Ministry of Housing, Communities and Local Government, 1 January 2026. Open Government Licence. Intersected with register points on this site. Most East of England towns are inset from the Green Belt that surrounds them, so far fewer register sites fall inside it than an authority-level tag suggests.
- National Planning Policy Framework (December 2024 revision) — Ministry of Housing, Communities and Local Government, 12 December 2024. Strengthened the expectation that brownfield applications will be approved, and required density uplift in urban areas.
- Brownfield Passport: Making the Most of Urban Land — Ministry of Housing, Communities and Local Government, 22 September 2024. Government working paper stating there are not enough sites on brownfield land registers to deliver the homes the country needs.