United Kingdom

Nuclear-armed state

Possesses 225 nuclear weapons

Has not yet joined the TPNW

SIGNED

RATIFIED

IN FORCE

Status

The United Kingdom has not yet signed or ratified the Treaty on the Prohibition of Nuclear Weapons (TPNW).

National position

The United Kingdom has consistently voted against an annual UN General Assembly resolution since 2018 that welcomes the adoption of the TPNW and calls upon all states to sign, ratify, or accede to it “at the earliest possible date”.

Along with other nuclear-armed states, the United Kingdom has said that it does “not accept any claim that [the TPNW] contributes to the development of customary international law”. It has called on all states that are considering supporting the the treaty “to reflect seriously on its implications for international peace and security”.

Doctors from Medact and its global federation, the International Physicians for the Prevention of Nuclear War, meet in York in 2017. Photo: IPPNW

Nuclear-weapon programme

The United Kingdom possesses approximately 225 nuclear weapons, which it can launch from nuclear-capable submarines based off the coast of Scotland. One submarine is usually on patrol at any given time.

In 2021, the United Kingdom announced that it would increase the limit on the size of its nuclear arsenal for the first time in decades. Instead of decreasing its nuclear stockpile to 180 warheads by the mid-2020s as previously planned, the United Kingdom intends to increase its stockpile to 260 warheads.

In 2024, the United Kingdom spent an estimated US$10.4 billion to build and maintain its nuclear forces.

The United Kingdom tested 45 nuclear weapons between 1952 and 1991. From 1952 to 1963, it conducted 12 nuclear test explosions and up to 600 so-called “minor trials” in Australia. Between 1957 and 1962, it tested (with the United States) 33 nuclear weapons at Malden and Kiritimati islands in Kiribati.

Political developments

More than 60 members of the Westminster parliament, along with dozens of members of the Scottish parliament and the Welsh assembly, have pledged to work for the United Kingdom’s signature and ratification of the TPNW.

In 2020, the then-first minister of Scotland, Nicola Sturgeon, wrote that “the Scottish government is firmly opposed to the possession, threat, and use of nuclear weapons” and “I have called on the UK government to sign and ratify the treaty”.

Ahead of the TPNW’s entry into force in 2021, Sturgeon said: “An independent Scotland would be a keen signatory [to the TPNW] and I hope the day we can do that is not far off.”

In 2020, more than 30 bishops and archbishops of the Church of England published a letter calling on the government to sign the TPNW. Many cities across the country, including Manchester, Brighton, Oxford, and Edinburgh, have also appealed for this.

Public opinion

A public opinion poll conducted in 2021 by Survation on behalf of the Campaign for Nuclear Disarmament found that 59 per cent of Britons believe that their country should join the TPNW, with just 19 per cent opposed to joining.

TPNW negotiations

The United Kingdom did not participate in the negotiation of the TPNW at the United Nations in New York in 2017 and thus did not vote on its adoption. On the opening day of the negotiating conference, it joined the United States and several other states in protesting the treaty-making process.

In 2016, the United Kingdom voted against the UN General Assembly resolution that established the formal mandate for states to commence negotiations on “a legally binding instrument to prohibit nuclear weapons, leading towards their total elimination”.

The United Kingdom actively discouraged other states, in particular its former colonies, from supporting the resolution.

A public opinion poll conducted by YouGov ahead of the TPNW negotiations in 2017 found that 75 per cent of British people believed that their government should participate in the negotiations, with 9 per cent opposed to participating and 16 per cent undecided.

A Japanese paper crane sits on the empty desk of the United Kingdom during the TPNW negotiations in New York in 2017. Photo: ICAN

ICAN campaigners meet in London in 2015 to discuss progress towards negotiations on a future treaty prohibiting nuclear weapons. Photo: ICAN

Further information

Nuclear Weapons Ban Monitor

United Kingdom

Nuclear-armed state

Possesses 225 nuclear weapons

Has not yet joined the TPNW

Status

National position

Nuclear-weapon programme

Political developments

Public opinion

TPNW negotiations

Further information

Local Partner Organizations

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