On 30 October 2023, the Secretary of State (“SoS”) on a recovered appeal refused to grant planning permission for a ‘hyperscale’ data centre within the Buckinghamshire Green Belt on the outskirts of Greater London.
Situated within the Slough Availability Zone (“SAZ”), a recognized area for data centres spanning multiple counties, the 52-hectare former landfill site adjacent to the M25, south of Slough Road, was earmarked by developers for outline consent for data centre development (B8 (data centre)) of up to 163,000sqm across three buildings.
The proposed development, aimed at meeting the growing demand for data infrastructure, was refused on the basis of significant concerns regarding harm to the Green Belt, the potential adverse effects on the area's character and appearance, and the availability of alternative sites.
The crux of the case rested on the conflicting considerations of the urgent need for additional data centre capacity versus the protection of the Green Belt.
The SoS agreed with the Inspector that there is “significant and substantial demand” for data centres within the SAZ and across the UK, the provision of which would “make a significant contribution to the UK economy” and the proposed development would make a significant contribution to this need.
Notably not in dispute at Inquiry was the need for circa 2,665MW of extra data centre capacity within London between 2022 to 2027.
In reaching the decision, the SoS acknowledged that the absence of an alternative site within the SAZ, the site's advantageous location (near the Iver substation), and the creation of local education and employment initiatives all carried moderate weight in favour of the proposed development.
While the SoS recognised that there were no alternative sites for the proposed development in the SAZ, the SoS accepted the Council’s position that there were other Availability Zones which were not within the Green Belt, noting that the applicant had carried out no analysis of those sites.
Weighing against the proposed development, the SoS concluded, was the harm to the Green Belt from inappropriate development along with harm to the openness and purpose of the Green Belt. The SoS concluded that the considerations for development did not constitute very special circumstances to outweigh the harm to the Green Belt and to the character and appearance of the area.
Accordingly, the SoS agreed with the Inspector’s recommendation, dismissed the appeal and refused to grant consent.
Use Class Considerations
The decision did not consider the planning use classification and the SoS did not question or analyse the categorisation of the data centre as Class B8 (storage).
A degree of uncertainty continues to surround the appropriate planning use class for data centres. As the use of data centres continues to evolve then we might expect some further clarification or confirmation through decisions that they are within Use Class B8 as most LPAs seem to think. Data centres not only store data but play a key role as hubs in receiving, converting and distributing information as well as running cloud processes and applications. Over time this may characterise the use as one that is more unique than a subset of storage.
Until the government issues national guidance, or the Use Classes Order is amended, or further binding decisions in the Courts, we will likely have to wait for a clear and definitive approach taken to data centre planning use classification. Currently this question appears to be one for the decision maker based on the facts of each case.
Data centre development in the Green Belt: Very Special Circumstances, Alternatives and Public Benefits
At the heart of the refusal was a failure to look outside of the SAZ for non-Green Belt sites on which the development could be located. Data centre developers should take care when promoting Green Belt development to ensure that a suitably thorough assessment of sites has been carried out both within the relevant Availability Zone and in other Availability Zones. The acknowledged need for data centre development alone was not sufficient to constitute very special circumstances in this case. A wider assessment of alternative locations could have shifted the balance in favour of a grant of planning permission.
Arguably it should not fall to an applicant to assess every single potential data centre site in the London (or wider) area where there is such an urgent acknowledged need for data centre capacity. Clear central government policy support for data centres as a critical part of the UK’s digital infrastructure seems to be needed now more than ever.
Data centre developers should not lose hope - the very special circumstances test remains a balancing exercise - in simple terms, the planning benefits of the development must clearly outweigh all harms arising from the development.
Whilst Woodlands Park fell short of achieving very special circumstances, this does not mean all Green Belt data centre applications would do the same. Promoters should ensure that the public benefits of a proposed development are a) as substantial as possible and b) clearly and robustly articulated.