What is the status of Britain’s new nuclear warheads?

A recent research briefing from the House of Commons Library has revealed new details about the UK’s ongoing programme to replace its nuclear warhead.

The programme, which is currently in its concept phase, aims to ensure the UK’s nuclear deterrent remains effective beyond the life of the current system.

The replacement warhead programme was confirmed by the government in February 2020, following a disclosure by a US official. Since gaining Cabinet Office approval of its Strategic Outline Case in September 2021, the programme has moved forward in its early stages.

The concept phase is crucial as it examines the feasibility of different procurement options and identifies performance, cost, and time parameters.

The House of Commons Library briefing notes, “The Concept phase is an opportunity to examine the feasibility of different procurement options and to identify performance, cost, and time parameters for the programme.”

Estimating the costs of the replacement warhead programme remains challenging. The 2006 White Paper suggested that the cost would be between £2-3 billion, equivalent to £2.8-£4.3 billion in 2022/23 prices.

However, precise cost estimates are not yet available due to the evolving design requirements.

The MOD has indicated, “Given that the Replacement Warhead Programme is still in its early stages, it is too early to provide cost estimates… as much will depend on the eventual design requirements.” So far, £127 million has been spent on preliminary work up to March 2021.

Several factors are expected to influence long-term cost estimates, including the complexity of the programme, commercial arrangements, and collaboration with the United States and its W93 programme. The MOD confirmed in March 2023 that work is underway to agree on cost estimates and funding arrangements, suggesting independent management of the programme from the Nuclear Warhead Capability Sustainment Programme (NWCSP).

The new Labour government has announced a multi-year spending review set to conclude in Spring 2025. This review, alongside a new strategic defence review to report in the first half of 2025, will consider the efficiency and effectiveness of the nuclear programme.

Since 2006, the UK has been working on programmes to maintain its nuclear deterrent, including the development of the Dreadnought-class ballistic missile submarines, expected to enter service in the early 2030s. The decision to replace the Mk4/A nuclear warhead was initially deferred in 2010 but confirmed as part of the Government’s Integrated Defence and Security Review in 2021.

The February 2020 disclosure by a US official about the UK’s replacement warhead programme led to the government’s confirmation of the programme, which was criticized for its lack of transparency and parliamentary scrutiny.

For more details, the full report “Replacing the UK’s nuclear deterrent: The Warhead Programme” is available on the House of Commons Library website.