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United Kingdom

Nuclear-armed state (NATO)

The United Kingdom boycotted the TPNW negotiations in 2017 and remains unwilling to adhere to or engage constructively with the Treaty.

TPNW Article 1(1) prohibitions: Compatibility in 2021
(a) Develop, produce, manufacture, acquire Not compatible
Test Compatible
Possess or stockpile Not compatible
(b) Transfer Compatible
(c) Receive transfer or control Not compatible
(d) Use Compatible
Threaten to use Compatible
(e) Assist, encourage or induce Not compatible
(f) Seek or receive assistance Not compatible
(g) Allow stationing, installation, deployment Compatible
TPNW voting and participation
2021 UNGA resolution on TPNW
2020 UNGA resolution on TPNW
2019 UNGA resolution on TPNW Voted no
2018 UNGA resolution on TPNW Voted no
Participated in TPNW negotiations No
Share of women in TPNW negotiations N/A
Vote on adoption of treaty text N/A
Adoption of TPNW (7 July 2017) N/A
IAEA safeguards and fissile material
Safeguards Agreement Voluntary offer agreement
TPNW Art 3(2) deadline N/A
Small Quantities Protocol No (Signed 1993)
Additional Protocol Partial
Fissile material production facilities Yes (Civilian)
Highly enriched uranium stocks 21.9 tons (m), 0.7 tons (c)
Plutonium stocks (mil/civ) 3.2 tons/116.1 tons
Related treaties and regimes
Party to the BWC Yes
Party to the CWC Yes
Party to the PTBT Yes
Ratified the CTBT Yes (Annex 2 state)
Party to the NPT Yes
Party to a NWFZ No (4 of 5 NSA protocols)
Member of the CD Yes

Latest developments

In a joint statement in the First Committee of the 2021 UN General Assembly, the United Kingdom, together with China, France, Russia, and the United States, reiterated its opposition to the TPNW.1

In 2017, the government said that the United Kingdom 'does not intend to sign, ratify or become party to' the TPNW. It further stated that '[t]he unpredictable international security environment we face today demands the maintenance of our nuclear deterrent for the foreseeable future.'2

Despite the UK government's position, the devolved government in Scotland has repeatedly voiced its opposition to nuclear weapons and support for the TPNW.3

The cities of Edinburgh and Manchester have joined ICAN’s Cities Appeal.


  • 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. It should move rapidly to verifiably reduce and eliminate its nuclear arsenal.
  • 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.
  • The United Kingdom should implement in good faith its obligations under Article VI of the NPT. The United Kingdom should also upgrade to a Comprehensive Safeguards Agreement and requisite Additional Protocol with the IAEA.

Inventory of nuclear warheads at the beginning of 2022

Total inventory of warheads
Retired warheads
Usable stockpile of warheads
Total yield of usable stockpile
Hiroshima-bomb equivalents
United Kingdom ubat

All of the 180 Holbrooke warheads are assigned to the Trident II D5 submarine-launched ballistic missiles (SLBMs) that are carried by the United Kingdom’s Vanguard-class ballistic missile submarines (SSBNs). The United Kingdom maintains a policy of continuous at-sea deterrence, meaning that one of its four SSBNs is on deterrence patrol at all times. Two other submarines are available for deployment, while the fourth boat is in refit. Each submarine can carry up to 16 Trident II D5 SLBMs, though each submarine carries only 8, totalling 40 deployed warheads at-sea at any given moment. The patrolling SSBN operates at ‘reduced alert’ status, meaning that its capability to fire its missiles is measured in days, rather than a few minutes.

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