Grey Belt demystified: From green to grey

In December 2024, the government updated the NPPF and finalised some pro-development reforms to liberalise planning and encourage housebuilding, focusing on developing ‘grey belt’ areas as well as other strategies to address the housing crisis.

In this article, you will learn the concept of the grey belt, how it fits with the government’s housing strategy, and whether it will help to address the UK's chronic housing shortage.

Let’s begin by uncovering exactly what grey belt land means.

The ‘grey belt’ is a concept introduced by the Labour Party to identify poor-quality, underutilised sections within the Green Belt.

These areas don’t have significant levels of biodiversity and aren’t used for public enjoyment and as such, are seen as potential sites for new housing developments to address the UK’s acute housing crisis. This includes previously developed land and/or areas of Green Belt that make a limited contribution to the Green Belt’s key purposes.

Labour’s planning reforms aim to utilise these grey belt lands to contribute to their ambitious target of building 1.5 million homes. These plans are intended to address the housing crisis while also preserving the integrity of more valuable Green Belt land.

After a long wait, grey belt land was finally defined in the finalised NPPF.

It says:

‘For the purposes of plan-making and decision-making, ‘grey belt’ is defined as 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.’

For context, footnote 7 includes designations for environmental protection, including habitat sites, Sites of Special Scientific Interest, Areas of Outstanding Natural Beauty, and National Parks. 

And what are Green Belt purposes a, b and d?

a) to check the unrestricted sprawl of large built-up areas
b) to prevent neighbouring towns merging into one another
d) to preserve the setting and special character of historic towns

While this definition broadly fits with what we expected, more detail could have added clarity and streamlined the process of distinguishing grey belt land from the Green Belt. Plus, given most Green Belt designated land contributes to at least one of these Green Belt purposes, it may be tricky for councils to confidently identify land that meets this criteria. Nonetheless, it is a start.

According to The Times, 3% of England’s Green Belt has the potential to be considered grey belt, which includes previously developed land such as former industrial sites and quarries. This amounts to about 46,871 hectares of land with significant potential for housing development. 

The Times highlights that 6% of the Green Belts in Birmingham and Blackpool could be classified as grey belt. Similarly, Cheltenham and Gloucester, have 5% and South and West Hampshire have 4% of Green Belt land that could be deemed grey.

Before we go any further, it’s crucial to pinpoint a couple of Green Belt myths that, in my opinion at least, are mostly to blame for these changes not going ahead sooner.

If you’re worried that these changes mean environmental destruction, then I need you to read the two key points below.

Let’s take a look.

One common Green Belt misconception is that all Green Belt land is verdant and pristine. While there is no denying that much of the Green Belt is truly green, there is also a large amount that isn’t as lush as we are led to believe. In reality, only 59% of it is agricultural land, with much of the remaining land being former industrial sites or land of little environmental value.

In fact, 76% of London’s Green Belt consists of low environmental quality land, containing defunct agricultural buildings and areas with minimal biodiversity. Additionally, a large part of the Green Belt is privately owned and not accessible to the public, challenging its role as a public resource.

Though many people believe that the Green Belt exists to protect wildlife, special landscapes, and historic assets, the reality is that the Green Belt policy isn’t primarily concerned with environmental preservation; its primary purpose is to contain the expansion of cities and prevent urban sprawl. 

With this in mind, the term 'green' can be misleading, as the designation and protection of Green Belt land is based on its location rather than its environmental or scientific value.

As part of their Green Belt reform, the government has pledged to prioritise developing grey belt and brownfield land, grant new devolved planning powers to regions, and reform compulsory purchase rules for faster land assembly. 

The new government will also identify locations to create a series of new towns to help alleviate housing shortages. This involves building entirely new communities with integrated infrastructure, public services, and green spaces. The objective of these new large-scale towns is to provide high-quality, affordable housing and foster sustainable residential-led developments.

The relaxations in the planning process for building within the Green Belt will be guided by new ‘golden rules’ which include:

to improve local or national infrastructure and 3) to create or improve green spaces that are accessible to the public.

Additionally, when it comes to allocating Green Belt land for development, LPAs have been instructed to first consider brownfield land, then grey belt areas that are not previously developed, before reviewing other Green Belt locations for housing development as their final option.

The Campaign to Protect Rural England (CPRE), a lobbying group with strong beliefs against building in the Green Belt, has expressed nuanced and sometimes mixed reactions to the concept of grey belt development. In short, CPRE's view on grey belt could be described and summarised as cautiously supportive. 

Although CPRE acknowledged the necessity of developing some genuinely low-quality grey belt land, the group has consistently advocated for prioritising brownfield sites, asserting that there is enough brownfield land to build all the homes we could possibly need. 

But, the reality is there is simply not enough brownfield land in the UK to accommodate the demand for housing. It is calculated that even if all brownfield land with development potential was redeveloped, it would supply only 970,000 dwellings. So, if you went down that path, it would only provide enough housing to meet demand for the next four years. 

What happens when those years have passed?

Furthermore, CPRE believes that some areas, even if currently degraded, have the potential to be rehabilitated into valuable habitats. Therefore, their suggestion is to evaluate each site on its individual merits, considering its potential for environmental restoration and community use.

The organisation also warned against the risk of speculative development, where landowners might deliberately degrade land to get it reclassified as grey belt, thus qualifying it for development. Therefore, CPRE argued that stringent environmental standards and comprehensive planning are essential to ensure that grey belt development does not lead to environmental degradation.

We believe that an independent commission can be established to provide the necessary oversight and uniformity to address these concerns effectively. This body could ensure that grey belt classifications are made transparently and equitably, preventing unethical practices and ensuring that environmental integrity is maintained.

An often-overlooked point is that allocating grey belt land for development requires navigating the complex dynamics between local priorities and national standards. Because local authorities often focus on immediate economic benefits, this approach can overshadow the need for long-term environmental sustainability. 

Conversely, national guidelines and design codes that standardise practices across regions might not deliver the type of relevant housing solutions effectively, leading to a one-size-fits-all approach that lacks local context, the unique characteristics and needs of individual local authorities. 

Another critical challenge in implementing grey belt policies is managing regional disparities. An analysis conducted by Knight Frank, which identified over 11,000 grey belt sites across England, also highlights that these sites are not evenly distributed. Remarkably, 41% of these sites are concentrated within London’s Green Belt, with significant numbers also found in Greater Manchester, Birmingham, and South and West Yorkshire. 

This uneven distribution implies that some regions may gain more from grey belt development than others, potentially intensifying regional disparities in housing availability and economic growth. Addressing these disparities requires careful planning and targeted support for regions with fewer grey belt opportunities.

The simple truth is that if we are to meet the growing demand for housing in the UK, it is essential that we release some Green Belt land for development. The release of even a small percentage of the Green Belt, including low-quality grey belt land, could significantly help accommodate several years' worth of housing needs but only if planned and designed holistically.

The government has also recently announced it is reinstating mandatory local housing targets, which were relaxed by the previous government. To that end, by local councils releasing publicly owned grey belt land to national housebuilders and SME developers, the delivery of new sustainable communities can be significantly accelerated.

Our team of Green Belt architects and planning consultants is fast earning a reputation as one of the country’s leading planning and architecture firms - particularly when it comes to Green Belt planning permission - and we know how to produce results that meet the expectations of the council while exceeding those of our clients. 

Please do get in touch if you’d like to discuss your project.

The Green Belt is one of the most contentious and misunderstood pieces of planning policy in England and it’s a topic we at Urbanist Architecture have a lot of experience working with. For this reason, we decided to pool our learnings and pen a book delving deep into the Green Belt from every possible angle.

‘Green Light to Green Belt Developments’ investigates the policy's biggest winners and losers and explores its connections to climate change and the housing crisis, as well as what the future might hold. It also looks at the history of the policy and how it’s managed to endure while other policies have evolved and adapted with the times. Of course, it also identifies the Green Belt exceptions and very special circumstances that exist for permitting development in the Green Belt, so you can better your chances of gaining planning permission.

We’ve written this book for anyone seeking a more rounded understanding of one of England's most debated urban planning issues, making it accessible to both industry professionals and the general public.

Whether you are a landowner in the Green Belt wishing to understand the potential for land value uplift or a developer planning to build new homes in the Green Belt, this book is an essential read. Order your copy now.