UK-based data centre operator Ark Data Centres has unveiled plans for a significant expansion of its London Edge presence with a £2 billion development of a new hyperscale data centre campus near Watford. The project, on the site of the former Mercure Hotel, is expected to deliver up to 200 MW of critical power capacity across multiple facilities and is being positioned as one of the largest data centre developments in Europe.
The proposed campus will consist of up to six two- to three-storey data centre buildings designed to support a broad range of workloads, including cloud, enterprise, government, and advanced AI applications. Construction is anticipated to begin in 2026, with the first buildings targeting operational readiness around 2029.
A notable factor supporting the project’s viability is the existing power reservation of 120 MW at the nearby Elstree substation, secured by the site’s previous owner and now included in Ark’s plans. This significant power allocation, coupled with the site’s strategic location in the London commuter belt, positions the campus to meet growing demand for high-density compute and low-latency connectivity.
The development is expected to contribute to local economic growth, with the creation of hundreds of jobs during construction and ongoing roles once operational. It also raises important considerations around sustainability, cooling efficiency, and environmental impact, particularly as energy-intensive AI workloads become an increasingly prominent part of the data centre ecosystem.
Planning approval from Hertsmere Borough Council and community engagement will be key next steps as the project progresses through consultation and regulatory review.
IST-DATA Insight
Large-scale data centre campuses like Ark’s new London development underscore the increasing technical and operational complexity of delivering mission-critical electrical infrastructure in support of hyperscale and AI workloads. Independent electrical design assurance, structured commissioning and testing, and robust safety systems of work are essential to manage risk and ensure compliance throughout development and energisation. IST-DATA’s specialist services — from readiness verification and defect identification to operational governance and post-commissioning support — help developers and operators achieve safe, compliant, and reliable electrical systems capable of meeting the demands of next-generation digital infrastructure.
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