United Kingdom
The United Kingdom is expanding its nuclear arsenal. Along with all other nuclear-armed States, it boycotted the negotiations on the Treaty on the Prohibition of Nuclear Weapons (TPNW) in 2017. Since then, it has consistently voted against the annual UN General Assembly resolutions on the Treaty, including in 2025. It may sign and ratify the TPNW at any time but will have to destroy its nuclear weapons in accordance with a legally binding, time-bound plan and make other changes to its policies and practices to become compliant.
TPNW Status
| Nuclear warhead inventory at the beginning of 2025 | ||
|---|---|---|
| Total inventory of warheads | 225 | |
| Retired warheads | 0 | |
| Warheads available for use | 225 | |
| Estimated yield (MT) | 22.5 | |
| Hiroshima-bomb equivalents | 1500 | |
| Key weapons of mass destruction treaties | ||
|---|---|---|
| NUCLEAR WEAPONS | ||
| Party to the TPNW | No | |
| Party to the NPT | Yes (Ratified 1968) | |
| Ratified the CTBT | Yes (Ratified 1998, Annex 2 state) | |
| Party to an NWFZ | No (4 of 5 NSA protocols) | |
| CSA with the IAEA | Voluntary offer agreement | |
| AP with the IAEA | Partial (In force 2004) | |
| BIOLOGICAL AND CHEMICAL WEAPONS | ||
| Party to the BWC | Yes (Ratified 1975) | |
| Party to the CWC | Yes (Ratified 1996) | |
| TPNW Art. 1(1) prohibitions: Compatibility in 2025 | ||
|---|---|---|
| (a) | Develop, produce, manufacture, acquire | Non-compatible |
| Possess or stockpile | Non-compatible | |
| Test | Compatible | |
| (b) | Transfer | Compatible |
| (c) | Receive transfer or control | Non-compatible |
| (d) | Use | Compatible |
| Threaten to use | Compatible | |
| (e) | Assist, encourage or induce | Non-compatible |
| (f) | Seek or receive assistance | Non-compatible |
| (g) | Allow stationing, installation, deployment | Non-compatible |
| TPNW voting and participation | |
|---|---|
| UNGA resolution on TPNW (latest vote) | Voted no (2025) |
| Participated in 3MSP (2025) | No |
| Participated in 2MSP (2023) | No |
| Participated in 1MSP (2022) | No |
| Average MSP delegation size (% women) | N/A |
| Adoption of TPNW (7 July 2017) | N/A |
| Participated in TPNW negotiations (2017) | No |
| Negotiation mandate (A/RES/71/258) | Voted no |
| Fissile material | |
|---|---|
| Nuclear facilities | Yes |
| Fissile material production | Yes (Civilian) |
| HEU stocks | 23 Mt (22 Mt available for weapons) |
| Plutonium stocks | 119.6 Mt (3.2 Mt available for weapons) |
| SQP with the IAEA | N/A |
Latest developments
At the Treaty on the Non-Proliferation of Nuclear Weapons (NPT) Preparatory Committee meeting in April 2025, the United Kingdom said that its nuclear arsenal ‘remains essential to guarantee our security and that of our Allies in NATO’, and it intends to maintain ‘a minimum, credible nuclear deterrent for as long as the security situation requires’. ‘The fundamental purpose of our nuclear weapons is to preserve peace, prevent coercion, and deter aggression,’ it argued.1
It also claimed that ‘NATO’s status as a nuclear alliance offers collective deterrence and assurance, protecting global peace and security whilst limiting proliferation’. NATO’s nuclear-sharing arrangements, it said, are and have always been ‘in full conformity with the NPT’.
In June 2025, the UK government published its Strategic Defence Review, which suggested that the UK Ministry of Defence ‘should commence discussions with the United States and NATO on the potential benefits and feasibility of enhanced UK participation in NATO’s nuclear mission’. Such discussions could open the door for the United Kingdom to deploy air-launched tactical nuclear weapons.2
In July 2025, UK campaigners urged the government to confirm whether US nuclear bombs had recently been re-deployed to RAF Lakenheath in Suffolk, England, for the first time since 2008.3
In the First Committee of the UN General Assembly in October 2025, the United Kingdom argued that it remains fully committed to the goal of a world without nuclear weapons. ‘This commitment is not just set out in fine words. It is how we act,’ it said.4
In April 2024, prior to being elected Prime Minister of the United Kingdom, Keir Starmer wrote: ‘My commitment to NATO and the UK’s nuclear deterrent—maintained on behalf of NATO allies—is unshakeable. Absolute. Total.’ He described the United Kingdom’s development of nuclear weapons in the 1950s as a ‘towering achievement’ that ‘defined modern Britain’ and pledged to build all four planned Dreadnought-class nuclear-armed submarines to replace the current Vanguard-class fleet.5 In an interview with the BBC, he declared his willingness to use nuclear weapons if elected.6
All of the United Kingdom’s nuclear weapons are currently based in Scotland, where political support for the abolition of nuclear weapons is strong. In March 2024, the Scottish government said that ‘nuclear weapons should not be based in Scotland and should be removed from Scotland in the safest and most expeditious manner possible following [Scotland’s] independence’.7
Recommendations
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The United Kingdom should acknowledge that nuclear deterrence is not a sustainable solution for its own or international security, and that any perceived benefits are far outweighed by the risk of nuclear accidents or war.
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The United Kingdom should comply with its existing obligation under Article VI of the Treaty on the Non-Proliferation of Nuclear Weapons (NPT), and pursue negotiations in good faith on nuclear disarmament.
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The United Kingdom should urgently adhere to the TPNW. Until it is in a position to do so, it should welcome the TPNW as a valuable component in the global disarmament and non-proliferation architecture, work with the Treaty's states parties on practical steps towards disarmament, and attend the meetings of states parties as an observer.