Exclusive: Sheffield’s secret lab working on the UK’s next nuclear warheads

A research centre at the University of Sheffield is playing a major role in the Ministry of Defence programme to develop a new nuclear warhead, The Tribune can reveal.

We have found evidence of a ‘secure cell’ established at the Advanced Manufacturing Research Centre (AMRC) since at least 2022. This unit was set up by the secretive MoD body responsible for developing nuclear weapons — the Atomic Weapons Establishment (AWE). The purpose of this ‘cell’ is to assist the development of a new warhead for the UK’s nuclear arsenal, known as Astraea.

We gave both the Ministry of Defence and the university the opportunity to dispute our reporting. They did not. The combined authority has confirmed they are aware of the relationship between AWE and AMRC.

The nuclear effort in Sheffield has included the AWE placing staff directly at the AMRC, and the procurement of machinery to make prototype components and analyse uranium. It also appears to be the biggest research contract in AMRC’s history.

Sheffield has a long history of anti-nuclear activism, with the council declaring itself nuclear-free in the 1980s. But there has been no public discussion of the university’s participation in this work.

Very little is known about the Astraea programme. But a tip off by a single source earlier this year led The Tribune to uncover a series of documents which proved the AMRC’s involvement. They included minutes of meetings, a job advertisement and procurement notices linked to a secret project code.

We were also able to establish via planning notices that the project is based in the AMRC’s Design Centre. When The Tribune visited, there was minimal evidence of security in place beyond some cameras, with no one stopping us from looking around and photographing some of the recent changes to the building.

AWE operates out of an ultra-secure site in Aldermaston, Berkshire, protected by dogs and armed guards. Last year, AWE announced that it had “commenced work on a sovereign replacement warhead, as part of an evolutionary cycle that ensures we have an in-service warhead that can be safely assured from design to disposal.”

The AMRC told us last week: “Our collaboration with partners in the defence sector helps them to overcome sustainability and productivity challenges, and support UK security and sovereign capabilities. All research projects undergo rigorous oversight, including comprehensive due diligence, adherence to national legislation and health and safety regulations.” They also stressed they were not making components “for deployment”.

David Cullen, former head of research body the Nuclear Information Service, and a policy expert on the UK’s nuclear weapons programme, said: “The evidence gathered by The Tribune clearly shows that AMRC is working on uranium components in collaboration with AWE. I have no doubt that the University of Sheffield is a partner in the early stages of the Astraea programme. I think both AWE and AMRC owe the public an explanation.”

Read all about the journey to report this story included anonymous messages from insiders, secret project codes, uranium, and the moment we discovered the ‘secure cell’ in Sheffield. Available here.

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