NBIS London Longcross

Longcross Park in Surrey hosts Nebius's first UK deployment at an Ark Data Centres campus. Its significance is practical: it gave Nebius a local base for serving UK customers before the larger national expansion announced in June 2026.

The current evidence supports a purpose-built AI deployment within Ark's campus. The earlier version of this study connected the site's military and film-production history too directly to the construction of the data halls. That connection did not establish that Nebius's equipment occupies reused tank-testing or studio buildings. Ark describes purpose-built capacity and modular construction, which is the more reliable basis for understanding the facility.

The Nebius Data Center Tracker and complete infrastructure overview connect Longcross with the other UK and international deployments.

What Ark disclosed

Ark's June 26, 2025 announcement identified a long-term agreement with Nebius for Longcross Park, an initial deployment of 4,000 NVIDIA Blackwell Ultra GPUs and purpose-built, liquid-ready data halls. The announcement expected operation during the fourth quarter of 2025. Ark's Nebius agreement.

That announcement establishes the host relationship and the planned initial equipment scale. It does not establish an exact current GPU inventory or a measured electrical load. A GPU deployment can expand, change configuration or move through customer acceptance without a corresponding change to the campus's public description.

The deployment is now part of a wider UK programme

Nebius's June 8, 2026 announcement said its first UK Blackwell Ultra deployment had launched in November 2025. It announced three additional deployments and approximately £1.7 billion of investment across a four-site programme expected to reach 65 MW when fully ramped in 2027. That is a national total, not a revised allocation to Longcross. Nebius's UK expansion.

Longcross and Harlow consequently belong in the same UK directory but remain separate sites. Later announcements, including additional host relationships, should be recorded individually rather than folded into the first UK campus.

Building design and workload requirements

Ark's current Longcross page describes modular steel construction and both air and liquid cooling. These features are relevant to equipment installation and future changes in rack density. They are design characteristics, not evidence of a particular measured power usage effectiveness or a guarantee that all installed equipment uses liquid cooling. Ark Longcross Park.

An AI cluster also needs network capacity, storage and dependable power distribution. The useful operating question is whether the complete system can serve customer workloads consistently. A high rack-power rating on its own cannot answer that question or establish customer utilization.

What the location contributes

A UK deployment gives customers a local service option and can simplify requirements concerning where their data and workloads run. Whether it meets a particular customer's sovereignty, security or procurement requirements depends on the actual service and contract. A domestic address does not automatically satisfy every such requirement.

Longcross provides an established starting point for the national buildout. The next evidence to follow is customer availability and any specifically disclosed expansion at this campus. The earlier study's detailed claims about continuous 16 MW consumption, exact hall layouts and inherited military structural advantages are not carried forward as verified operating facts.

For the commercial analysis and separately dated model reports, continue to the Nebius company page. This site study was reviewed through September 17, 2026.