Hyperscale Data Centre approved on Grey Belt site

The much-anticipated appeal by Greystoke Land, in respect to a hyperscale data centre proposal at Abbots Langley has been allowed. On 12 May 2025, on behalf of the Secretary of State, the Under-Secretary of State for Housing and Local Government granted planning permission, following the Three Rivers District Council decision to refuse the scheme.

This decision is an important one, setting yet another strong precedent for data centre development in the Green Belt. It follows hot on the heels of the planning permission granted (via recovered appeal) for a data centre by Affinius Capital at Court Lane, Iver (further details here) on 06 December 2024. The Abbots Langley decision should serve to provide the industry with a further boost of confidence when pursuing proposals through the planning system. The decision confirms a demonstrable need for data centre development and provides further clarity on the application of ‘Grey Belt’ policy.

The Greystoke Land scheme at Abbot’s Langley includes for a hyperscale data centre (Parcel 1) of up to 84,000 sqm (GEA) and the creation of a country park (Parcel 2).

The Inspector's assessment identified varying degrees of landscape and visual impact on the surrounding area, less than substantial harm to designated heritage assets, harm to non-designated heritage assets, and the loss of best and most versatile arable farmland. However, the Inspector also recognised extensive benefits.

These benefits include addressing the urgent need for data centre capacity in the Hemel Hempstead Availability Zone and the wider London Availability Region, for which no plan-led solution currently exists. The development would bring substantial investment of around £1 billion, whilst generating many highly skilled jobs and wider economic benefits. Additionally, it would improve public access to the countryside and deliver a 135% Biodiversity Net Gain. Importantly, the site was considered to constitute ‘Grey Belt’ and as such was not considered inappropriate development in the Green Belt. The appellant did not therefore have to demonstrate Very Special Circumstances.

On balance, the Inspector concluded that the benefits of the proposal clearly outweighed the identified harms, and that material considerations supported granting planning permission.

The development was judged to constitute 'Grey Belt' land, as it did not 'strongly' contribute to purposes (a), (b) and (d) of NPPF Green Belt policy. Specifically, when assessed against purpose (a), parcel 1 was found to have a moderate contribution, as the existing features (M25 motorway to the north, Bedmond Road to the west and existing settlement to the southwest) “would act as a strong physical boundary to any further outward encroachment”, thereby checking unrestricted sprawl. The inspector also determined the site did not strongly contribute to the remaining Green Belt purposes and the development would not fundamentally undermine the remaining Green Belt within the district. It was accepted that there is a demonstrable need for the development and it was common ground that the Site is in a sustainable location. As such, the development accorded with the relevant tests set out in Paragraph 155 of the National Planning Policy Framework (NPPF).

We now eagerly await the outcome of the third such recovered appeal for data centre development in the Green Belt. This relates to another Greystoke proposal for West London Technology Park at Woodlands Park landfill site.

JLL benefits from a wealth of experience in respect to Data Centres, offering a 'cradle to grave' service that includes site finding, site selection, planning, advisory, transactions, and facilities management. To discuss any of the matters discussed above or any other planning matter, please contact the team.