The Grey Belt: The 2025 Planning Policy Update

On February 27, 2025, the Ministry of Housing, Communities and Local Government (MHCLG) unveiled new Planning Guidance that redefines how we view the Green Belt, and introduces the concept of the "Grey Belt." This shift aims to balance our cherished green spaces with the pressing need for residential development. 

Let's dive into what this means for developers, planners, and green-thumbed enthusiasts alike.​

What's New in the ONS Affordability Data? What Exactly is the "Grey Belt"?

The Grey Belt has two key roles: ‘plan making’ and ‘decision taking’.

When it comes to plan-making, think of the Grey Belt as the Green Belt’s more flexible cousin. While the Green Belt exists to curb urban sprawl and protect rural areas, the Grey Belt identifies pockets of land within it that could be suitable for development—without compromising those core green space protections. And it’s not just about repurposing derelict car parks; any land within the Green Belt could be assessed for Grey Belt potential, regardless of its previous use.

For decision-taking, the Grey Belt acts as a policy mechanism that allows certain Green Belt sites to be redeveloped—without having to meet the 'Very Special Circumstances' (which are usually required for Green Belt development). If a site meets the necessary tests, it can bypass the usual lengthy Green Belt review process and move forward with development more smoothly.

How Is Grey Belt Land Identified?

The process involves a multi-step assessment:

• Contribution to Green Belt Purposes – Grey Belt assessment focuses on three key Green Belt purposes:
  
  
  • Preventing urban sprawl.
  • Preventing the merging of towns.
  • Safeguarding the setting of historic towns.

Interestingly, while these purposes focus on managing development at the edges of urban areas, they don’t directly protect all green spaces within the Green Belt. 

• Footnote 7 Restrictions – Sites are checked for constraints such as Sites of Special Scientific Interest (SSSI), ancient woodlands, or national parks, which can limit development potential.

Basically, if a site doesn’t strongly contribute to the specified Green Belt purposes and isn’t burdened by significant restrictions, it might be considered Grey Belt land.

Not All Grey Belt Land Is Fair Game for Development

Just because a site could be Grey Belt doesn’t mean it’s automatically up for grabs. Identifying Grey Belt land is just the first hurdle—before a site is deemed suitable for development, it has to pass a few key tests:

• Be in a Sustainable Location – If a site is miles from the nearest shop, school, or bus stop, it’s not exactly an ideal place to build homes. Proximity to public transport and amenities is a must.
• Address Unmet Housing Needs – The site should be in an area where housing demand is high, not just where developers fancy building.
• Follow the ‘Golden Rules’ – Developments should respect the openness of the Green Belt and provide accessible green spaces—because adding houses doesn’t mean losing all open space, just using it more thoughtfully. A key part of the Golden Rules is also ensuring that developments include affordable housing at a rate of 50%, or 15% above the locally adopted rate, helping to meet the growing demand for homes while maintaining the integrity of the Green Belt.

Only when a site clears all these hurdles can it be considered appropriate for development within the Green Belt framework—because in planning, a good location is about more than just postcodes and potential.

Key Takeaways From the Release of the 2025 PPG

• Broad Application: Grey belt isn't limited to previously developed land; it can apply to any land within the Green Belt.​
• Town-Centric Focus: Green Belt purposes pertain to towns, NOT villages.​
• Development Scrutiny: Even if land is identified as grey belt, it doesn't guarantee development approval.​
• Counter-Intuitive Findings: Some open countryside near urban areas might not meet Green Belt criteria, challenging traditional notions of what should be protected.​

Our Approach to Identifying Suitable Development Sites

We’ve refined our assessment process to align with the latest planning guidance, ensuring that every site is evaluated with precision, logic, and a healthy dose of common sense:

• Grey Belt Evaluation – Not all land is created equal, so we assess each parcel against Green Belt purposes, scoring it as Strong, Moderate, or Weak. Think of it like a football league—some sites are in the Premier League of protection, while others are more… Sunday League.
• Sustainability Assessment – We check how well-connected a site is to transport and amenities. If you’d need a survival kit and a sherpa to get to the nearest shop, it’s probably not making the cut.
• Agricultural Land Classification – If it’s prime farmland (Best and Most Versatile land), we believe it should stay that way—because no one wants to be the person who paved paradise and put up a parking lot.
• Unmet Need Analysis – Using the 'Presumption in Favour' status of local planning authorities, we identify areas crying out for new housing (because, let’s face it, house prices aren’t getting any friendlier).

By applying this robust, data-led approach, we ensure that our clients receive the most accurate, up-to-date, and realistic assessments possible. We’re not just giving you an answer; we’re also helping you justify it. 

Because when it comes to planning, gut feeling won’t get you very far—but solid evidence and smart analysis just might.

Where Is Land Really Being Released for Development?

We’ve assessed every parcel of land within the Green Belt, giving each a rating of High, Moderate, or Low suitability — based on a bespoke scoring system aligned with the Grey Belt tests.

Using this analysis, and a few reasonable assumptions (60% of any site is developable, and densities range between 40–60 dwellings per hectare, or ha), the potential is striking: nearly 11 million new homes could be delivered by using less than 20% of the total Green Belt.

Our results closely align with many of the sites already approved as Grey Belt — which is reassuring. That said, we can’t say for certain how many of these sites will make it through the next hurdle: meeting the Golden Rules and satisfying LPAs. That’s in the hands of planners, developers, and — inevitably — a few planning inspectors and barristers along the way.

Take a look at the map below and click on the different areas to see exactly what land is being earmarked for development. Dph = dwellings per hectare.

And if we focus only on the Highly ranked sites? You’re still looking at serious potential — between 900,000 and 1.4 million homes on just a little over 2% of the total Green Belt.

Conclusion

The 2025 Planning Guidance doesn’t just redraw the lines on a map—it introduces a more nuanced way of balancing much-needed development with Green Belt preservation. It’s not about opening the floodgates or shutting them entirely; it’s about smart, evidence-based decision-making.

By understanding and applying these guidelines, stakeholders can cut through the complexity of grey belt identification and make informed choices that support both sustainable urban growth and environmental responsibility. In short, it’s about building where it makes sense.

Want to see how LandTech can help identify 'Grey Belt' opportunities? Speak to one of our experts by clicking below.