Era4 and Cosine Sign MoU to Scale Britain’s Sovereign AI Capability

Era4 and Cosine have signed a Memorandum of Understanding (MoU) to collaborate on the development of Lumen Sovereign, one of the UK’s first truly sovereign frontier large language models (LLMs).

Developed by British AI company Cosine, Lumen Sovereign is being built to operate with no dependence on foreign infrastructure, providing a secure and sovereign AI capability for defence, financial services, healthcare and other regulated sectors. Trained entirely on UK-owned and operated infrastructure, the model is designed to enable organisations to deploy frontier AI while retaining full governance control over their data and workloads.

Lumen Sovereign will initially use Isambard-AI, the UK’s most powerful supercomputer, and under the agreement, Era4 and Cosine have agreed to collaborate on the development of the model including exploring broader UK Sovereign AI Infrastructure beyond Isambard, with the shared objective of enabling Cosine to scale without capacity constraints.

Karl Havard, Chief Commercial Officer at Era4, said:

"Collaborations like this are critical to the scaling of the sovereign AI industry in the UK. Lumen Sovereign will be one of the first frontier AI models to be, designed, trained and deployed entirely under UK control. With this agreement, Era4 is helping ensure Lumen won’t have to compromise on sovereignty.”

Building the Infrastructure for Sovereign AI

Cosine was part of the first cohort of companies selected to receive support through the UK Government's Sovereign AI Fund, reflecting its role in strengthening Britain's sovereign AI capabilities.

As demand for sovereign AI grows, resilient domestic infrastructure will be critical. Era4 is helping to enable that ecosystem by providing the flexible, high-performance, lower-carbon capacity that organisations need to deploy AI with confidence.

In addition to the company’s data centre site in Chesterfield, which will be going live in Q2 of this year, Era4 owns more than 40 sites across the UK, with land and access already secured, enabling rapid deployment of new AI-ready facilities to help meet growing demand from UK businesses.