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United Kingdom

Nuclear-armed state (NATO)

The United Kingdom has the world's fifth largest nuclear arsenal. In 2022, it again demonstrated that it lacks the will purposefully to pursue nuclear disarmament. It remained unwilling to adhere to or engage constructively with the TPNW

TPNW Status

Nuclear warhead inventory at the beginning of 2023
Total inventory of warheads 225
Retired warheads 0
Stockpiled warheads 225
Estimated yield (MT) 22.5
Hiroshima-bomb equivalents 1500
TPNW Article 1(1) prohibitions: Compatibility in 2022
(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
UNGA resolution on TPNW (latest vote) Voted no (2023)
Participated in 1MSP (2022) No
1MSP 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
Other weapons of mass destruction (WMD) treaties
Party to an NWFZ No (4 of 5 NSA protocols)
Party to the NPT Yes (Ratified 1968)
Ratified the CTBT Yes (Ratified 1998, Annex 2 state)
Party to the BWC Yes (Ratified 1975)
Party to the CWC Yes (Ratified 1996)
IAEA safeguards and fissile material
Safeguards agreement Voluntary offer agreement
TPNW Art 3(2) deadline N/A
Small Quantities Protocol No
Additional Protocol Partial
Enrichment facilities/reprocessing plants Yes (Civ)
HEU stocks 21.9 tons (Mil)/0.7 tons (Civ)
Plutonium stocks 3.2 tons (Mil)/116.1 tons (Civ)

Latest developments

In the First Committee of the UN General Assembly in October 2022, the United Kingdom, in a joint statement with France and the United States, stated that ‘Progress on the nuclear disarmament agenda is only possible if we were to have an incremental, inclusive, consensus-based, multilateral process that takes into account the prevailing international security environment.’1

In January 2022, an early-day motion marking the first anniversary of the TPNW’s entry into force was tabled in the UK Parliament. It expressed regret ‘that the United Kingdom is neither a signatory of or a party to the Treaty’ and called on the UK government to ‘take urgent steps to comply with the provisions of the Treaty’.2

In June 2022, the then First Minister of Scotland, Nicola Sturgeon, reiterated her commitment to ensure that an independent Scotland would adhere to the TPNW, arguing that its possible membership of NATO should not serve as an impediment.3 In March 2022, the Welsh Senedd passed a motion calling on all states to sign and ratify the TPNW.4


  • 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.

  • The United Kingdom should comply with its existing obligation under Article VI of the Treaty on the Prohibition of Nuclear Weapons (NPT), and pursue negotiations in good faith on nuclear disarmament.

  • 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.

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