Cosine secures industry backing for Britain’s first sovereign frontier model

Cosine, the British AI company selected by the UK Government as part of its Sovereign AI initiative, today announced that it has brought together a coalition of leading UK institutions to co-design Lumen Sovereign, which it describes as Britain’s first sovereign frontier AI model.

Founded in 2023 in London, Cosine is a British sovereign AI frontier lab developing advanced models and coding agents that top public benchmarks — purpose-built for defence, national security and regulated industries where foreign-built AI is off the table and assurance by design is non-negotiable. 

Its platform can run entirely within a customer’s own infrastructure, with no external dependencies, delivering frontier AI that is developed, deployed and operated under full UK control.

Babcock International Group, BT, Lloyds Banking Group, LSEG, NatWest Group, PwC, Thales UK, BAE Systems, Leonardo UK, and Telefónica Tech UK&I are amongst the companies to have signed memoranda of understanding to participate in the model's design phase.

The coalition reflects the fact that many of the UK's largest institutions are increasingly seeing AI as a strategic dependency risk. Just as organisations have spent years reducing reliance on single energy suppliers or foreign-controlled communications infrastructure, a growing number of the UK's defence, financial and public sector institutions are reaching the same conclusion about AI. 

For some organisations, greater control over where AI models are trained and operated is becoming an increasingly important consideration.

Lumen Sovereign is to be trained entirely on Isambard-AI, one of Europe's most powerful supercomputers, using compute awarded through the UK Government's £500m Sovereign AI programme. 

MOU signatories will work directly with Cosine to define the use cases, security requirements and governance standards Lumen Sovereign must meet.

The model is designed to be deployed entirely within a customer's own infrastructure, with no external data transfer. Lumen Sovereign is targeted for deployment readiness by the end of 2026.

Priority applications include cybersecurity and adversarial testing, KYC and AML alert investigation, clinical trial coordination, legal document review and healthcare administration — workflows where the combination of sensitivity and complexity has made AI adoption difficult or impossible under existing tools. 

Cosine has assembled one of the largest collections of domain-specific training datasets outside the hyperscalers, spanning more than 30 regulated industry workflows, to ensure Lumen Sovereign can operate across the full breadth of coalition members’ needs.

According to Alistair Pullen, CEO and co-founder, Cosine:

“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.

Vendor lock-in creates security risk, dependency risk and cost escalation risks.  Cosine is addressing those risks by building a model that is fully trained on UK soil and available into air-gapped environments at a far more efficient price point than OpenAI and Anthropic alternatives.”

Chris Keone, MD, Innovation, BT, commented:

"As AI becomes a foundational technology for the UK economy, our customers need confidence that the systems they depend on are secure, trusted and aligned with their requirements.

This collaboration reflects our belief that innovation is strongest when industry, government and technology partners come together to build the foundations for future."

Lumen Sovereign will be developed using proprietary datasets built entirely in-house across pre-training, mid-training and post-training, rather than being adapted from an existing open-source checkpoint.

Lead image: Cosine.