Nebius has expanded to full capacity at Ark Data Centres' Longcross campus in Surrey, filling the LP01 building and increasing its UK presence.
The expansion comes as Ark has secured planning approval to enlarge the site for more AI-focused data centre infrastructure. At the campus, 16MW of capacity is already operational, with another 3MW being delivered.
Nebius has taken the remaining space in LP01 after an earlier deployment at the site. The latest move brings the building to full occupancy and reflects demand for operational infrastructure that can support AI workloads.
Longcross is one of a growing number of UK data centre locations being adapted for denser computing environments as cloud providers seek sites that can handle intensive GPU-based processing. Approved plans for the campus include vertical extensions to existing buildings, a new data centre known as DC03, and supporting infrastructure upgrades.
Those changes are intended to support higher-density deployments while maintaining the existing campus layout and environmental framework. The site is being positioned to meet changing customer requirements linked to AI computing.
Campus growth
The build-out of AI infrastructure has become a more prominent issue for operators, investors, and policymakers as demand rises for compute capacity tied to model training and inference. In the UK, that has sharpened attention on where suitable power, land, and planning consent can be secured for new or expanded facilities.
Deployments at Longcross are already live and expanding. Ark described the Nebius agreement as a sign that customers are moving from initial deployments to larger commitments at operational sites.
According to Ark, the Surrey campus supports workloads in areas including healthcare and scientific research. The infrastructure is used for applications such as earlier disease detection and data-led drug discovery.
That focus reflects a wider market trend: data centres are increasingly being marketed not simply as storage and hosting facilities, but as sites for specialist processing linked to AI development and deployment. For providers such as Nebius, access to established facilities can offer a faster route to expansion than building new sites from scratch.
UK demand
Ark said the Longcross expansion underlines growing demand in Britain for AI infrastructure that is already operational. It added that the project strengthens its role in serving large-scale cloud and technology customers with demanding technical requirements.
Nebius described the expansion as part of its UK growth plans, saying access to operational infrastructure is an important factor as organisations increase their use of AI tools and services.
"Demand for high-performance AI infrastructure is no longer theoretical - it is live, operational, and growing. Seeing customers scale from initial deployments to full-building occupancy is a clear validation of what has been delivered at Longcross. Securing planning permission for the next phase of development allows us to build on that momentum and continue supporting customers as their requirements evolve, while reinforcing our long-term commitment to enabling advanced digital infrastructure in the UK," said Huw Owen, chief executive officer of Ark Data Centres.
Ark was founded in 2005 and develops and operates data centres in the UK for public and private sector customers. It also works with the UK government through Crown Hosting Data Centres, its joint venture with the Cabinet Office.
For Nebius, the larger footprint at Longcross provides access to more capacity in a market that remains strategically important for AI deployment. The company said the site's reliability and performance informed its decision to expand its presence there.
"The UK is an important market for AI development and deployment, and access to high-quality, operational infrastructure is critical to supporting that growth. Expanding our work with Ark ensures we can continue to scale our platform and support organisations building and applying AI at scale," said Korolenko.