Tech bosses urge £20bn-plus sovereign AI commitment in Cosine-coordinated letter, City AM reports

Senior figures from BT, Telefónica Tech, Leonardo, HPE, Kainos and Sopra Steria have signed an open letter calling on the government to commit more than £20bn to sovereign AI infrastructure, City AM reported on 28 September 2026. City AM says the letter was coordinated by the British AI lab Cosine. The Times also reported the call earlier on 28 September.

What the letter asks for

According to City AM, the letter is addressed to Andy Burnham, the Prime Minister, who City AM reports has pledged to use Britain's G20 presidency to seek common international standards for safe AI, and AI minister Kanishka Narayan, and argues that AI should be treated as "strategic national infrastructure" alongside other critical assets. The requests City AM lists:

• A five-year programme spanning computing power, data centres, energy and government procurement.
• A Sovereign AI Capability Plan published within 90 days.
• A cross-party, 10-year strategy to give companies greater certainty over investment.
• Backing for British models in areas such as cyber security, defence, science and public services.
• Critical infrastructure that does not rely on a single AI model or tech stack.

City AM quotes the signatories: "Countries with reliable access to compute, secure deployment pathways, strategic models, and effective procurement will have greater resilience and influence." And: "Countries that lack those capabilities risk becoming dependent on decisions, infrastructure and operating conditions determined elsewhere".

The letter also pushes back on the idea that this means going it alone. "This is not a case for technological isolation", it says, per City AM; the paper reports that the letter wants Britain to keep working with allies while maintaining domestic capabilities where foreign dependence would create a national risk.

Who is behind it

City AM describes Cosine as developing the British frontier model Lumen. Cosine said Britain should use long-term contracts, planning and energy policy to make the country more competitive for training and deploying advanced AI, according to the report. Cosine also called for secure national data environments in which strategically important models could be trained on British government, defence and NHS data, subject to privacy safeguards and auditing, City AM reports.

Three of the named companies, BT, Leonardo and Telefónica Tech, are in a Cosine coalition. In a blog post dated 8 June 2026, Cosine announced a coalition to co-design its Lumen Sovereign model, listing BT, Leonardo and Telefónica Tech UK&I among the institutions providing input, alongside BAE Systems, HSBC, Lloyds Banking Group and others. Cosine describes Lumen Sovereign as "Britain’s first fully sovereign frontier AI model"; that is the company's own description.

Where the government already is

City AM notes that ministers have already set up a £500m Sovereign AI fund to back British AI companies and give them access to state computing resources and procurement opportunities. Last month, the paper reports, the government launched the first competitions under a £100m procurement scheme aimed at giving smaller British AI companies public sector contracts. City AM quotes Narayan saying at that launch that the programme would put "the heft of a nation behind Britain’s AI founders".

City AM describes Cosine's proposals as "a significant expansion" of the existing programme. By our arithmetic, on the figures City AM gives, the £20bn-plus ask is at least 40 times the size of the £500m fund.

Why it matters

On our reading, the letter moves the sovereign AI debate from a single fund to a multi-year spending commitment, and its signatories come from telecoms, defence and IT companies. City AM says it was coordinated by Cosine; on our reading, Cosine stands to benefit from the policies it proposes, which readers may want to weigh. City AM's report carries no government response to the £20bn figure.