United Kingdom
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.
Recommendations
- 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
Of the United Kingdom’s usable stockpile, 120 warheads are thought to be operationally available for deployment. The remaining 60 are in storage, together with up to 45 retired warheads that will be reconstituted to increase the stockpile to no more than 260. As shown below, the United Kingdom relies on just one type of weapon system for nuclear deterrence.

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.
Development, production, or acquisition of nuclear-weapons systems in 2021
The United Kingdom has committed to a comprehensive nuclear modernization programme that includes replacing its SSBNs, re-entry vehicles, and warheads. This programme is expected to keep nuclear weapons in the UK military arsenal until at least 2065.
- The United Kingdom is replacing its current fleet of Vanguard-class SSBNs with a new class, known as Dreadnought. These new submarines will likely enter service in the early 2030s.
- The United Kingdom is currently refurbishing its warheads for incorporation onto the US-supplied Mk4A aeroshell, which includes new technology – specifically, a new arming, fuzing, and firing system – that significantly increases the system’s ability to conduct hard-target kill missions.
- The United Kingdom is commencing a new warhead programme based on the United States’ new W93 warhead, and is reportedly lobbying the US Congress to expedite the W93 in support of the United Kingdom’s warhead replacement programme.3