A public inquiry has opened into a data center planned for green belt land near Slough, UK.

The data center would provide 107MW of capacity from a building spanning 448,000 sq ft (41,600 sqm). If approved, construction is expected to start in the first half of 2026. The site could eventually be expanded to offer 147MW.

First proposed earlier this year, a battery energy storage system would be built alongside the data center, with at least some power coming from an unnamed renewable and low-carbon energy firm.

It was called in for inquiry by the government’s Department of Housing, Communities, and Local Government following an appeal for the applicant. The council had not made a decision on the plan, but was set to reject it.

Developer Manor Farm Propco, a company set up by property investor Tritax Big Box to pursue the data center project, says that though the plot of land is in the green belt, it is “underutilized brownfield land.” Indeed, part of the land, which is adjacent to the Wraysbury Reservoir and the Poyle Industrial Estate, is currently occupied by commercial buildings, while some of it is farmland.

Manor Farm Propco said the site “comprises previously developed land that has secured numerous permissions for intensive commercial and industrial activities, establishing the principle of industrial development at the appeal site. It currently houses a range of different uses which are entirely consistent with the character of the wider area.

The council’s argument is that the need for the data center has not been proven, and as such, there is no good reason to build over the green belt.

“The proposed development would result in the further coalescence of Slough and Greater London and the further loss of the separate identity of Slough,” a council statement said. “It has not been demonstrated that it is essential for the proposed data center and battery storage facility to be in this location within the strategic gap between Slough and Greater London.”

Secretary of State Steve Reed will decide whether to approve the application following the conclusion of the eight-day public inquiry, which opened on Tuesday, October 14, and is being held at the Borough Council’s offices.

With the UK government keen to encourage more data center developments, Reed’s predecessor as Secretary of State, Angela Rayner, recently approved two data center developments, in Hertfordshire and Buckinghamshire, despite them having initially been turned down by local planners.

The area around Slough and Heathrow has historically been the UK’s busiest data center market, with the likes of CyrusOne, Vantage, Digital Realty, Yondr, Iron Mountain, DataBank, Colt, AWS, and Equinix all having a presence in the region.