Britain’s first sovereign AI model secures blue-chip backing as Starmer unveils £400m plan
Sir Keir Starmer’s push to build sovereign British AI capability has won backing from some of the country’s biggest companies, with BT, HSBC, Lloyds, Natwest and BAE Systems joining plans to develop Britain’s first sovereign frontier AI model.
British AI startup Cosine unveiled a coalition of major banks, defence contractors and infrastructure firms who had signed up to help design “Lumen Sovereign”, a UK-built frontier model that will be trained entirely on British infrastructure.
The announcement came as Starmer used the opening of London Tech Week to set out a more interventionist approach to AI, arguing Britain must ensure it remains in control of the technology underpinning its economy.
“Government is active in its approach to this, supporting risk-taking, making its own bets, providing the conditions for businesses to thrive, but also making sure we are sovereign,” the prime minister announced. “That is our path: Britain leading this new revolution in technology with our firms at the front and our people at its heart.”
Lumen Sovereign will be trained entirely on Isambard AI, one of Europe’s biggest supercomputers, using compute awarded through the government’s £500m Sovereign AI programme.
Cosine said the model would run without dependence on foreign infrastructure and could be deployed entirely within a customer’s own systems, an increasingly important consideration for organisations handling sensitive data.
Alongside BT, HSBC, Lloyds Banking Group, NatWest and BAE Systems, coalition members include Babcock, LSEG, PwC, Thales UK, Leonardo UK and Telefónica Tech UK&I.
The companies will help shape the model’s governance standards, security requirements and commercial applications before a planned deployment in 2026.
Starmer pushes homegrown AI
The corporate backing comes as ministers seek to turn Britain into a global AI powerhouse while reducing dependence on Big Tech and overseas tech providers.
Starmer on Monday announced a new sovereign compute strategy, including £400m of spending on specialist AI chips and plans to expand Britain’s national AI computing capacity.
“Today, I’m really pleased to announce a new strategy to develop sovereign compute capability,” he said. “It includes a major new commitment to purchase specialist AI chips worth about £400m.”
The prime minister also said government would take a more active role in supporting domestic tech firms, arguing that Britain’s next generation of AI champions should “start here, scale here and stay here”.
The announcement lands amid growing debate about whether Britain can build its own frontier AI capability rather than relying on American giants such as OpenAI, Anthropic and Google.
Cosine chief executive Alistair Pullen said concerns around security, cost and dependency were pushing organisations to look for alternatives: “AI is the single most important technology of our generation. Enterprises are increasingly waking up to the risk of being wholly dependent on foreign providers for this technology.”
The model is expected to be used across areas including cybersecurity, anti-money laundering investigations, legal document review, healthcare administration and clinical trial coordination.
The launch also comes as Britain’s AI sector continues to accelerate, with igures unveiled at London Tech Week showing UK AI startups have already raised more than $11bn this year, while the wider UK technology sector is now valued at $1.6tn.