UK tech leaders are calling on the government to invest much more heavily in sovereign AI.

In an open letter to Andy Burnham and AI minister Kaniska Narayan, executives from defense, financial services and critical national infrastructure firms say there's an urgent need to strengthen public confidence and national resilience.

Signatories include AI lab Cosine, PA Consulting, BT, Telefónica Tech, Leonardo, HPE, Kainos and Sopra Steria.

"AI is now a question of national capability. Countries with reliable access to compute, secure deployment pathways, strategic models, and effective procurement will have greater resilience and influence," the letter reads.

"Countries that lack those capabilities risk becoming dependent on decisions, infrastructure and operating conditions elsewhere."

The group wants to see financial support of at least £20 billion over the next five years, through public investment, procurement guarantees, and co-investment. This, they said, should be targeted at establishing sovereign British AI compute, power, data-center capacity, and network infrastructure for government, defense, academia, and strategic industry.

It's calling for changes to planning laws, energy policy, procurement, and long-term contracts to help AI firms, and a fast-track sovereign AI procurement route for urgent national priorities.

There should be financial backing for UK-led model development, with government, defense, and the NHS gaining access to proprietary British datasets for training these models, with strict privacy safeguards, mandatory audit trails, and interoperability standards.

"No mission-critical public service or critical national infrastructure should depend on a single model, provider, or cloud stack," Cosine said.

"Independent testing, evaluation and monitoring of AI models is essential to enable safe, secure and trusted AI adoption. Mandate tested fallback arrangements, independent alternatives, and human-in-the-loop control for all high-consequence AI systems."

The government, said the firms, should identify the areas of the AI value chain where the UK can become world-leading, then align infrastructure, procurement, research, regulation, and investment behind them. It should create a cross-party ten-year Sovereign AI Strategy with clear objectives, annual accountability, and long-term funding certainty.

Infrastructure, common standards, and interoperable systems should be shared with like-minded nations.

And it should identify the areas of the AI value chain where the UK can become world-leading, then align infrastructure, procurement, research, regulation, and investment behind them. It should create a cross-party ten-year Sovereign AI Strategy with clear objectives, annual accountability, and long-term funding certainty.

"Britain is coming from a position of strength. It has world-class research, deep software talent, strong cyber capability, credible institutions, strong digital infrastructure, and real advantages in science, defence and public services," the letter reads.

"But without a plan for AI sovereignty, the UK risks becoming a customer in the most important technological shift of this era, rather than a serious builder."

Earlier this year, the government launched a £500 million Sovereign AI fund aimed at helping domestic AI companies scale.

This will act as a venture capital fund within the government, making targeted investments in UK AI firms, and providing direct access to the UK's fastest AI supercomputers, along with specialist R&D support and grants.