How to fix the broken housing market

Should we build more homes on the Green Belt?

March 20, 2024 8 Minute Read

By Scott Cabot Jen Siebrits


The concept of a Green Belt originated in 1889, when Lord Meath proposed a Green Belt or girdle for London. The notion emerged more widely in the 1930s, and Green Belts were formally introduced in the 1947 Town and Country Planning Act. However, it wasn’t until 1955 that they were finally implemented into planning policy.

These areas were established around major cities with the primary objective of preventing urban spawl, along with protecting farmland, historic towns and other parts of the countryside, and encouraging urban regeneration. The Green Belt policy has been modified over the years, but its core objectives remain the same.

There are 14 Green Belts across England, totalling just over 1.6 million hectares (ha). Although it is under constant review, its overall size has remained relatively static in recent years, expanding by just under 2,500 ha since 2007. The Green Belt covers about 13% of the country, equating to an area 10 times the size of London.

Figure 1: Land designated as Green Belt across England, 2022


Source: Department for Levelling Up, Housing and Communities

A considerable number of homes could be built on this land, and by its very nature, the Green Belt surrounds urban areas where housing density is much higher than average. Using the housing density in outer London (of 16 homes per ha) as a proxy, suggests an upper limit of almost 25 million homes that could be built on the current Green Belt.

Of course, complete development of the Green Belt will never happen, and nor should it. They are vital, in some instances, to protecting natural landscape and habitats. However, a common misconception is that all the Green Belt is, in fact, ‘green’. The current terminology is a misnomer. It conjures images of lush natural landscapes when in fact, much of the land is used for intensive agriculture and there are large swaths of poor-quality Green Belt land. Almost two-thirds of the Green Belt is farmland with less than a fifth, or 310,000 ha, categorised as forest, open land, and water.

The Green Belt is fundamentally a land use policy. As such, the actual land designated as Green Belt may often have little inherent ecological value and isn’t chosen based on its natural beauty. These poor-quality Green Belt areas have recently been coined the ‘grey belt’ by the Labour Party, which incorporates areas that have either been neglected or previously developed.

Approximately 105,000 ha, or 7%, of the Green Belt is currently categorised as ‘developed’, which suggests this land is closest to existing urban areas. Again, using outer London as a proxy indicates that almost 1.7 million homes could be built on these sites. However, the density on major urban extensions typically averages 36 homes per ha. This means that the number of homes that could be accommodated on this small area of the Green Belt is potentially closer to 3.8 million. Specifically, in London there is a substantial number of these sites that are ripe for development, with many also close to existing transport infrastructure. As such, they could unlock a substantial amount of new homes, potentially allowing the capital to double its rate of annual housebuilding to 74,000 per year for the next 15 years. In addition, it’s often highlighted that these scattered plots of Green Belt land do nothing to meet the overarching aim of preventing urban spawl. Hence, these plots could be reallocated for development whilst keeping the remaining 93% of the undeveloped Green Belt intact.

Figure 2: Land use within the areas of the Green Belt categorised as ‘non-developed use’

Source: Department for Levelling Up, Housing and Communities

In fact, there has been a small amount of building permitted on the Green Belt. Since 2013, just over 3,000 ha of Green Belt land has changed to residential use, equating to 0.2% of its total area. The bulk of this has been on previously ‘non-developed’ areas, typically agricultural land. And over the last nine years, more than 24,000 homes were built on various Green Belts across the UK. Around 3,000 homes, or 13% of this total, has been in London’s Green Belt, which has a further 2,000 homes currently in the pipeline. However, building on the Green Belt is usually only granted in exceptional circumstances and gaining planning permission is typically more arduous, time consuming, and costly. For these reasons Green Belt development is generally avoided.

Building on the Green Belt will often garner opposition, and it remains highly protected. Most recently, the incumbent Government released a statement outlining proposals for building more homes on brownfield sites while protecting the Green Belt. However, the potential of building homes on the Green Belt should also be considered in the context of the national housing crisis. The lack of housing supply has contributed to an estimated 270,000 homeless people across England (123,000 of which are children), along with almost 1.3 million households on local authority waiting lists.

It should also be considered from the perspective of land availability. Currently, less than 10% of England’s land area is developed, with homes accounting for only 1%. This highlights the potential to take a balanced approach to Green Belt development, allowing homes to be built on specific areas without jeopardising our ‘green and pleasant land’.

As such, our view is that building on the Green Belt in a strategic, responsible, and sustainable way could be done at a larger scale than it is currently. Unlocking Green Belt sites for development could also convey broader benefits in terms of job creation and boosting economic growth at both a local and national level. However, unlocking land doesn’t necessarily translate into more homes. It simply translates into more development sites. In the absence of tackling other challenges to housebuilding – including wider planning reform – unlocking ‘grey belt’ or other Green Belt land may not significantly boost housing supply.


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