Building Lumen Sovereign: Cosine Forms Coalition with UK Industry Leaders

Cosine, the coding agent built for engineers with taste, led by Alistair Pullen, Sam Stenner, Yang Li, and the team, has announced the formation of a landmark industry coalition to co-design Lumen Sovereign, Britain’s first fully sovereign frontier AI model.

Building Sovereign AI Infrastructure for the UK.

With support from major UK institutions including BAE Systems, Babcock International Group, BT, Lloyds Banking Group, LSEG, NatWest Group, PwC, Telefónica Tech UK&I, Thales UK, and The Alan Turing Institute, Cosine is developing an AI platform designed to operate independently of foreign infrastructure.

The company’s Lumen Sovereign model is backed by the UK Government’s Sovereign AI programme and will be trained entirely within the UK using Isambard-AI, one of Europe’s most powerful AI supercomputers. The goal is to provide a domestically controlled AI capability for critical industries, strengthening national resilience, security, and technological sovereignty.

Reducing Strategic Dependence on Foreign AI Systems.

As AI becomes critical infrastructure, regulated industries increasingly face a tradeoff between adopting advanced AI capabilities and relying on models developed and operated overseas. Cosine argues that this dependence can create security, operational, and sovereignty risks for sectors such as defence, finance, and government.

Lumen Sovereign is intended to address those concerns by providing a UK-controlled large language model that can operate in highly secure and air-gapped environments while meeting domestic governance and regulatory requirements. Beyond security, a sovereign AI platform can also help organizations avoid vendor lock-in and reduce dependence on foreign AI providers.

To guide its development, Cosine is working alongside leading UK institutions to define the model’s use cases, security requirements, and governance standards from the outset, ensuring the platform is designed specifically for the needs of regulated industries.

Building Sovereign AI for Regulated Industries.

As AI becomes a critical layer of national infrastructure, organizations in defence, finance, and the public sector face growing risks from relying on foreign-developed AI systems. Cosine aims to address this challenge with Lumen Sovereign, a UK-built large language model designed for secure, regulated, and air-gapped environments.

Beyond strengthening security and data sovereignty, the platform is intended to reduce vendor lock-in and provide greater control over AI infrastructure. Cosine is developing the model in collaboration with major UK institutions to ensure it meets the security, governance, and compliance requirements of regulated industries from day one.

Positioning The UK As An AI Creator, Not Just A Consumer.

By bringing together leading organizations across the UK's critical infrastructure sectors, Cosine aims to build a domestically developed AI capability tailored to national priorities and regulatory requirements.

The broader goal is to strengthen the UK's technological sovereignty by ensuring that key AI systems are designed, trained, and governed within the country. Through Lumen Sovereign, the company hopes to help establish Britain as a builder of frontier AI technologies rather than solely a user of models developed elsewhere.