UK data center firm Ark is expanding one of its facilities outside London to accommodate Nebius.

The company this week announced the investment of £807 million ($1bn) in its campus at Longcross Park in Surrey, enabling AI cloud provider Nebius to expand its deployment at the site.

As part of the deal, Nebius will be leasing the entirety of the existing facility from Ark.

The approved expansion plans include vertical extensions to existing buildings, the development of an additional 36MW data center (LP02), and upgrades to supporting infrastructure across the site. Ark has committed £335 million ($449m) so far, with a further £472 million ($632m) promised.

Huw Owen, CEO, Ark Data Centres, said: “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.”

Nebius launched its London cluster at Ark’s Longcross Park campus late last year. The European cloud provider was initially set to lease 16MW, with a cluster of 126 racks across three data center halls using air-cooling and hot aisle containment.

The first phase was due to comprise 4,000 Nvidia HGX B300 GPUs, housed within Nebius’ self-developed Gen5 servers in air-cooled, hot-aisle containment. The planned second phase was set to comprise another 3,000 B300s.

News of the deployment was first announced in June 2025, with Ark naming itself as the host shortly afterwards.

Ark said the new expansion plans include enhancements designed to accommodate higher-density deployments and evolving customer requirements.

Situated in Chertsey’s 300-acre Garden Village and launched around 2024, Ark’s website says the Longcross site currently totals 54MW across two buildings.

Andrey Korolenko, chief infrastructure and product officer at Nebius, said: “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.”

Founded in 2005, Ark has 27 data centers across nine sites in operation or development across the UK and Belgium, totaling more than 560MW. It operates data center campuses at Cody Park in Farnborough, Meridian Park in north London, and Spring Park in Wiltshire’s Corsham, with a number of projects under development, including Union Park and Alliance Park in west London.

Controlled by Elliott Investment Management with Revcap as a minority investor, Ark also operates Crown Hosting Data Centres, a joint venture with the UK Cabinet Office focused on offering hosting to UK Government departments and agencies.

AI Minister Kanishka Narayan added: “The whole government is determined to create the right conditions for investment in the UK’s AI and data center infrastructure, to drive growth and create the jobs people deserve. Ark’s investment at Longcross Park is an important part of this work. This will bring more cutting-edge compute to the UK, which is critical to our plans to empower workers and turbo-charge productivity.”

Spun out from Russian Internet giant Yandex, Nebius has a data center presence across the US, the Middle East, and Europe.

This month saw Nebius announce a £1.7 billion ($2.26bn) investment in the UK, through which it will establish three new Nvidia infrastructure deployments.

As well as the Ark expansion, the cloud firm is deploying 22MW of GPUs at Kao’s Harlow campus outside London. The company hasn’t detailed the last expansion, but has said the three deployments will total 65MW of capacity when fully ramped up in 2027.

As well as owning a data center in Mäntsälä, Finland, the company is currently leasing or set to lease capacity in the UK, France, Israel, Iceland, Finland, and the US in New Jersey and Missouri.

Nebius is also planning a self-built facility outside Kansas City in Independence, Missouri, and planning a gigawatt-scale development in Pennsylvania. The company is also developing a 240MW data center in Béthune in northern France.