Navigating the New 'Grey Belt' Guidance: Opportunities and Challenges for Developers

On 27 February 2025, the UK government published new planning practice guidance (PPG), putting some more detail around the concept of ‘Grey Belt’ land within the Green Belt, which was introduced within the December 2024 NPPF update. 

This update provides some more certainty for developers who are looking at sites that may be considered as Grey Belt. Understanding the nuances of this policy is now essential for those seeking to unlock development potential in these areas.

What is 'Grey Belt' land?

The NPPF definition of Grey Belt is 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.

So, we already knew that Grey Belt sites were not affected by Footnote 7 constraints, and that they sites did not strongly contribute to three key Green Belt purposes:

•  Purpose (a): To check the unrestricted sprawl of large built-up areas.
•  Purpose (b): To prevent neighbouring towns from merging into one another.
•  Purpose (d): To preserve the setting and special character of historic towns.
  
  

Developments on Grey Belt sites were already being approved, both by LPAs as well as at Appeal, we’ve been keeping an eye on how these were falling, and how this related to our own analysis of Grey Belt sites.  There are a couple of public collations of Grey Belt decisions, we like this one from Marrons Planning.  The big question is, now that the PPG has been released, do these decisions align with the new guidance? 

What has the PPG added?

Firstly, the PPG has added some useful visual aids to help guide us through this process. Figure 1 shows us that a Site must not be affected by Footnote 7 constraints, and must not strongly contribute to Green Belt purposes a), b), or d).   

Figure 2 shows us that this isn’t the end of the story. Once you’ve identified that a site could be Grey Belt, you then need to demonstrate that: 

• You can provide the Golden Rules (affordable housing at 15% above the local limit -up to 50%),  improvements to local infrastructure, and improvements to local green spaces; and
• You can demonstrate that there is a need for the development. For housing developments this normally means that the LPA can’t meet it’s housing land supply, or housing delivery, requirements; and
• You can show that the loss of the site from the Green Belt would not undermine the performance of the remaining green belt; and
• You can show that the site is in a sustainable location.
  
  

If you can do all this, then development in the Green Belt is no longer ‘inappropriate’ and you don’t have to justify the ‘harm’ to the green belt that could be caused by the development by outlining the Very Special Circumstances that exist for the site’s development. 

Why this matters for Developers

The new guidance means developers must take a more strategic approach when identifying potential sites. The key considerations include:

1. 1. Site-Specific Evaluation: The intrinsic qualities of the site must be assessed in detail to determine whether it qualifies as ‘Grey Belt’ and is appropriate for development.
   
   
2. 2. Meeting Green Belt Purposes: Developers need to demonstrate that their proposals do not undermine Green Belt purposes (a), (b), and (d). Avoiding urban sprawl, preventing town coalescence, and protecting historic settings will be crucial in securing planning approval.
   
   
3. 3. Awareness of ‘Footnote 7’ Constraints: Developers must be aware of constraints listed under ‘Footnote 7’ of the National Planning Policy Framework (NPPF). These include Sites of Special Scientific Interest (SSSIs), designated heritage assets, and other protected areas. Early identification of these restrictions is critical to avoid wasted time and resources.
   
   
4. 4. The ‘Golden Rules’: The guidance introduces ‘Golden Rules’ for Green Belt development. While details are still emerging, these rules are likely to set clear parameters around what can and cannot be developed. Understanding and adhering to these will be vital for any successful application.
   
   
5. 5. Sustainable Location: The sustainability of the site will be a major factor in planning decisions. Developers must demonstrate that their proposed development is well-located in relation to infrastructure, public transport, and amenities, supporting wider sustainability goals.
6.  
7. 6. Council’s Housing Land Supply: Local planning authorities must demonstrate a five-year housing land supply and meet delivery targets. Developers who can show that their sites contribute to housing supply in underperforming areas may have a stronger case for planning approval.
   
   

How LandTech can help identify 'Grey Belt' opportunities

LandTech has been at the forefront of mapping ‘Grey Belt’ opportunities, providing crucial data to help developers make informed decisions.  Our initial research suggested that up to 150,000 hectares of land could qualify as ‘Grey Belt’, with the potential to deliver between 2.5 and 4 million new homes. The detail provided in the new PPG shows that this approach that we’ve taken is generally sound, and the new guidance has allowed us to introduce additional refinements to our approach to ensure that we’re being as useful as we can be to those who are looking to identify Grey Belt sites. 

Using LandInsight, developers can pinpoint possible Grey Belt sites quickly and efficiently, understanding how they compare to other possible Grey Belt sites, and reducing the time spent looking at unsuitable locations. 

With councils now required to review their Green Belt boundaries, and speculative applications expected across the board until this process is well progressed, having access to accurate data will be crucial in getting ahead of the curve.

Final thoughts

The introduction of ‘Grey Belt’ guidance marks a significant shift in Green Belt policy, offering new opportunities for housing development. However, developers must be prepared to meet stricter requirements around sustainability, constraints, and policy compliance.

By leveraging tools like LandInsight, developers can take a data-led approach to identifying viable sites, ensuring they focus their efforts on the most promising opportunities. As councils assess their housing supply and review their Green Belt areas, those who act now will be in the strongest position to bring forward successful developments.

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