The scheme proposed a data centre of up to 55,000m2 in volume with a maximum height of 28m together with ancillary buildings, access, and parking. The site lies in the metropolitan Green Belt, straddling the local authority boundary between Buckinghamshire Council and the London Borough of Hillingdon. Mirror-image applications submitted to both local planning authorities went undetermined following previous refusals of very similar schemes.

Although the site was already in a commercial use, the Inspector found that "the great height of the proposed development and its footprint would create a significantly more urban appearance" that the existing development, which would conflict with and erode the more verdant and less developed character of the wider area. This would be both harmful in character and appearance terms, as well as eroding the spatial sense of openness of the Green Belt and causing encroachment into the countryside. 

Notwithstanding the notable need for data centres both locally and nationally, and the significant weight to be afforded to the economic benefits of the proposal, the Inspector was not convinced that very special circumstances had been shown justifying the inappropriate development in the Green Belt. He also concluded that there was conflict with the development plan taken as a whole. Accordingly, the appeal was dismissed. 

A copy of the appeal decision can be found here. 

Brendan Brett acted for the London Borough of Hillingdon, instructed by Diana Miller of London Borough of Hillingdon Legal Services.