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Research & Analysis Published 26 Jun 2025 House of Commons Library ↗ View on Parliament

Strategic Defence Review 2025: The UK's nuclear deterrent

Type: Commons Briefing Paper (CBP-10275) What are the implications of the new Strategic Defence Review for the UK's nuclear deterrent?

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Strategic Defence Review 2025The UK's nuclear deterrent - House of Commons Library

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The UK operates a submarine-launched nuclear deterrent which it is currently renewing, with
a new fleet of submarines and a replacement warhead
for its Trident missiles.

In July 2024, the government commissioned a new Strategic Defence Review which it said would be conducted on the basis of
“a total commitment to the independent nuclear deterrent”
. The review would, however, consider the “efficiency and effectiveness of the nuclear programme”. The review was independently led, by the former Defence Secretary and former NATO Secretary General Lord Robertson.

The
government published the Strategic Defence Review
on 2 June 2025. The government has endorsed the vision set out in the review and accepted all 62 of its recommendations. The SDR says that £15 billion will be committed to the replacement warhead programme in this Parliament. The SDR also recommended that the government begin discussions with the US and NATO on greater UK participation in NATO’s nuclear deterrence mission. This raised questions about whether the government is considering buying nuclear-capable F-35A aircraft and allowing US nuclear weapons to return to the UK. The UK withdrew its own independent air-launched nuclear deterrent in 1998. The US removed nuclear weapons from the UK in 2008.

The
decision of the UK to join the NATO nuclear deterrence mission
was subsequently announced at the NATO summit on 24 June 2025. The government has confirmed that it will purchase 12 F-35A aircraft, although has not said where associated US forward deployed nuclear weapons will be based. The government has said that
the decision is compliant with the Nuclear Non-Proliferation Treaty
.