One year on – the impact of ‘grey belt’ in Hertsmere Borough

Our analysis shows that 302.45 hectares, the equivalent of approximately 470 football pitches, of open countryside within the Green Belt within Hertsmere Borough is now under threat of development as ‘grey belt’.

The concept of ‘grey belt’ was introduced in the revised National Planning Policy Framework (NPPF) a year ago in December 2024.  Since then, we’ve seen a significant increase in the number of speculative planning applications that argue that the proposed development site should be considered ‘grey belt’.

Government ministers state that they are committed to protecting the Green Belt from inappropriate development. They also insist that ‘grey belt’ is poor quality or previously developed land within the Green Belt, like disused car parks, derelict petrol stations and abandoned garages.

But our analysis of the impact of the concept of ‘grey belt’ on Hertsmere Borough shows this is not the case.

Since the introduction of ‘grey belt’, there have been 16 major planning applications for sites within the Green Belt in Hertsmere Borough, where the application has argued that the site constitutes ‘grey belt’.  Only 1 of these 16 applications is on previously developed land.

The other 15 applications cover 302.45 hectares (or the equivalent of about 470 football pitches) of open countryside within the Green Belt. These sites are not poor quality nor previously developed and they are most certainly not disused car parks, derelict petrol stations or abandoned garages. They are locally valued landscapes, mostly agricultural fields and pastures, usually with Public Rights of Way that provide local residents with their daily dose of nature.

Listed below are these 15 planning applications. The relevant sites are all throughout the Borough, in Aldenham, Borehamwood, Bushey, Elstree, Potters Bar, Radlett, Shenley and South Mimms.

We are appalled at the spate of speculative planning applications, not just in Hertsmere but across all of Hertfordshire, that are proposing developments in the Green Belt and arguing that the site is ‘grey belt’. This is why we are campaigning for a change in the Government’s definition of ‘grey belt’ and to restore the pre-existing Green Belt protections in national planning policy.

We are calling on the Government to urgently amend the definition of ‘grey belt’ to uphold Green Belt protections. Read more about our campaign and please also write to your MP to let them know of your concern on this issue. We’ve provided a template that you can customise before you send it.

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Hertsmere Borough planning applications for open countryside sites (not previously developed) within the Green Belt, where the application has argued that the site constitutes ‘grey belt’.