Launch of UK’s ‘largest AI supercomputer’ delayed by power supply problems

A huge datacentre project hailed by the UK government will miss its launch date next year and could be delayed into the mid-2030s.

The site in Loughton, Essex , was described as the country’s largest AI supercomputer when it was announced in 2025, but power supply problems mean it now faces a lengthy wait before coming online.

Doubts had already emerged about the scheme after the Guardian revealed in March that the planned location was still an operational scaffolding yard.

Now there are further concerns about the project due to its inability to obtain enough power before its planned 2027 debut. The Loughton supercomputer is being built by Nscale, a UK-based startup seeking a $35bn (£26bn) flotation this year.

UK Power Networks (UKPN), the company that will connect the site to the local power grid, has reportedly told Nscale the grid will not be able to supply sufficient power to the datacentre until the early to mid-2030s.

Nscale said it was “committed to the project” but the failure tofind a quick fix to the power supply issue underlines how much energy has become a hindrance to datacentre development. The scaffolding yard site has now been cleared by Nscale, however. The company is also investigating whether it can generate power onsite and whether it can speed up the connection process.

Keir Starmer’s government cited the Loughton project when announcing the UK’s AI strategy in 2025 , describing the site as the “largest UK sovereign AI datacentre”. Datacentres are the central nervous system of AI technology such as chatbots.

The scaffolding company, which was operating on the site. Photograph: Martin Godwin/The Guardian

Ofgem, the energy industry regulator, has warned of a logjam in applications for electricity connections . In June, it revealed there were 315 datacentres queueing to connect to the National Grid, representing 73GW of demand – compared with the peak energy demand for the entire country of 45GW.

The Loughton site is seeking up to 90MW of capacity, equivalent to the energy consumption of about 315,000 homes.

UKPN said it could not comment on an individual project. Schemes with large energy demand also require work to be done at a National Grid level, in order to ensure that energy demands can be met properly. “In general, many datacentres, whilst they will connect to our distribution network, are awaiting works on the wider national electricity transmission network before they can begin operation,” said a UKPN spokesperson.

National Grid said: “We’re continuing to work closely with Neso [the government-owned National Energy System Operator], distribution network operators and customers to identify opportunities to accelerate connections where possible and support economic growth.”

A government spokesperson said Neso and Ofgem were working to ensure the right projects were getting power connections under a reform of the application process. “We are reversing decades of underinvestment and delivering the biggest upgrade to the grid in decades.”

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