Grey Belt Planning: How to Get Permission for Your Custom Home
We help landowners and homeowners build eco-homes, extend their homes, and create unique holiday homes that gain planning permission and pay them back. RIBA Chartered Architects.
What is grey belt?
Grey belt is land inside the Green Belt that the planning system now treats differently. The idea arrived in the December 2024 Framework. The National Planning Policy Framework published on 17 August 2026 kept it, moved it to policy GB7(1)(g), and put the definition in Annex B. If an older guide cites "paragraph 155", it is talking about the same thing under the old numbering.
The practical point is simple. If your site is grey belt and the scheme passes the tests in GB7(1)(g), a new home is not inappropriate development in the Green Belt. You don't need to argue very special circumstances. For anyone holding a plot on the edge of a village, that is a big shift.
What counts as grey belt land
Annex B defines grey belt as Green Belt land that is previously developed, or any other land that does not strongly contribute to three of the five Green Belt purposes: checking the sprawl of large built-up areas, stopping neighbouring towns merging, and preserving the setting of historic towns.
The purpose that matters most in open countryside, safeguarding it from encroachment, is deliberately left out of the test. So a field can be grey belt even though building on it would encroach on the countryside. That surprises most landowners I speak to, and it is why grey belt works on sites that still look green.
Previously developed land. Old farmyards, redundant petrol stations, derelict buildings, hardstandings. If your site is previously developed, look at policy GB7(1)(e) as well. It allows redevelopment of previously developed land, including a change to residential use, where it would not cause substantial harm to openness. On some sites that is the simpler route.
Low-contribution greenfield land. Paddocks on the edge of a settlement, parcels boxed in by roads or existing development, fields that do very little Green Belt work in practice. Read your council's Green Belt Assessment first. It usually scores land parcel by parcel against the purposes, and it tells you quickly whether your site has a chance.
Why grey belt matters for a custom home
Before grey belt, a new house in the Green Belt was inappropriate development unless it fitted one of a few narrow exceptions, such as limited infilling in a village or redeveloping previously developed land. Anything else needed very special circumstances, now policy GB6(2), where the harm to the Green Belt carries substantial weight and has to be clearly outweighed. Most single-house cases never cleared that bar.
Policy HO11 (formerly paragraph 84) doesn't get you round it either. Inside the Green Belt, policy S5(5) switches off the countryside policies that lead to HO11, and the Green Belt policies apply instead. Exceptional design can help a very special circumstances case, but it isn't a route in its own right.
Grey belt changes the starting point. It doesn't guarantee permission: design, access, ecology and your local plan all still apply. But the principle of a home on the site is no longer something you have to argue against the full weight of Green Belt policy.
The tests in policy GB7(1)(g)
First, the land has to be grey belt under the Annex B definition. Then the scheme has to pass the tests in GB7(1)(g). All of them apply.
1. It must not fundamentally undermine the remaining Green Belt. The question is whether developing your site would weaken the Green Belt across the wider plan area. For one house on a small plot, this is rarely where a case falls down.
2. There must be a demonstrable unmet need. For housing, the usual starting point is the council's housing land supply position. Read the latest supply statement before you spend anything. Where the council cannot show enough supply, this test is much easier to meet. Where it can, a single custom home has a harder argument to make.
3. The site must be in a sustainable location. This test runs through policy TR3, which is about giving people a genuine choice of how they travel. It is the test I would worry about most. At South Nutfield in Surrey, an appeal decided on 18 September 2026 was dismissed on location alone, even though the site was accepted as grey belt and the housing need was clear. The inspector found residents would depend on their cars: no continuous footway, no street lighting, and a bus service too infrequent to be useful. Some earlier appeals accepted modest walkability for a single house. I wouldn't rely on that now. Walk the route to the nearest shop, school and bus stop before you do anything else.
4. Major housing must meet the Golden Rules. Policy GB8 sets affordable housing, infrastructure and green space requirements for major housing schemes. A single custom home is not major development, so this won't apply to you. It matters if you are thinking about several plots.
How to go about a grey belt application
There are two routes. The right one depends on how strong your grey belt case is and whether you need to de-risk the site before paying for design.
Route A: full planning application. One application covering the grey belt principle and the full design. It is quicker overall and suits sites that are clearly grey belt, such as previously developed land, or where a pre-application has come back positive.
Route B: Permission in Principle (PiP). A two-stage route that suits grey belt land well. The first stage only looks at location, land use and the amount of development: in your case, one house on this site. Design and technical detail follow later, at the Technical Details Consent stage.
That means you can establish that a home can be built on the site before paying for design work, surveys, structural engineers and technical reports. It also helps if you might sell. A plot with PiP is worth more than the same plot without it.
PiP makes most sense when the grey belt case is uncertain and you want to test it before commissioning design work, or when you may sell the land.
A full application makes more sense when the site is clearly grey belt, for example a disused petrol station, or when pre-application feedback has already been positive.
Where to start
Grey belt is the biggest change to Green Belt policy in decades, and it is still being tested at appeal. The sites that succeed are the ones checked properly before anyone draws a line.
Start with your council's Green Belt Assessment, its latest housing land supply statement, and a map of the walking route from your site to the nearest shops, school and bus stop. If all of them look reasonable, grey belt is worth pursuing. If one of them fails, you want to know now, not after paying for a design.
My free guide on building on land you've been told is unbuildable sets out grey belt alongside the other routes planning supports. You can download it below, or book a free 20-minute call if you'd like me to look at your site.
