Nuclear Disarmament United Kingdom


British nuclear-powered ballistic missile submarine HMS VANGUARD (SSBN-28), www.defenseimagery.mil

NPT Nuclear Weapons State

Arsenal Size

  • Total warheads: no more than 215 [1]
  • Operationally available warheads: no more than 120 [2]
  • Non-operational reserve: 95 (routine maintenance, processing, and logistic management) [3]

Weapon System

  • Four Vanguard-class SSBNs carrying a maximum of 8 operational U.S. supplied Trident II D5 Submarine Launched Ballistic Missiles (SLBMs). The United Kingdom’s policy of Continuous At Sea Deterrence (CASD) requires that one Vanguard-class submarine be on patrol at all times. [4]
  • In October 2016, construction began on the HMS Dreadnought, the first of the new Successor-class of SSBNs. The Dreadnought-class submarines will be the largest in the Royal Navy, and will be fitted with 12 missile tubes for the Trident D5 instead of 16. [5]
  • Each D5 missile carries, on average, three United Kingdom-produced warheads with a yield between 80 and 110 kilotons, which closely resemble the U.S. 100kt W76 warhead. [6] The reentry vehicles (Mk4) are in the process of being upgraded to Mk4A over the next couple of years. [7]
  • Several sources indicated in June 2008 that the United States withdrew nuclear weapons from the RAF Lakenheath Air Base, where it is generally believed that 110 U.S. nuclear weapons used to be deployed. [8]

Estimated Destructive Power

  • Operationally available warheads: Approximately 16 megatons. [9]

Military Fissile Material Stockpile

Disarmament and Commitments to Reduce Arsenal Size

  • Legal obligation to pursue global disarmament under Article VI of the Treaty on the Non-Proliferation of Nuclear Weapons (NPT). [12]
  • The United Kingdom is the only nuclear weapon state (NWS) with a single weapon system, and is the NWS with the smallest nuclear arsenal. [13]
  • During the 1970s arsenal size peaked at 520 warheads. [14] Currently estimated to contain no more than 120 operational warheads. [15]
  • Since 2010, the United Kingdom has decreased the number of warheads on each submarine from 48 to 40, decreased the requirement for available warheads from 160 to 120, and decreased the number of operational missiles on each submarine to 8. [16]
  • The last of the 100 WE 177 A/B Nuclear Gravity Bombs (NGB) was dismantled at AWE Aldermaston in 1998. [17]
  • In accordance with its cessation in 1995 of fissile material production, the United Kingdom has decommissioned or is currently decommissioning fissile production facilities, or has converted them for peaceful use. [18]
  • The UK-Norway Initiative is a collaborative project between the United Kingdom and Norway, begun in 2007, to develop a verification system for warhead dismantlement. The project has hosted exercises, meetings, and workshops for nuclear weapon states and non-nuclear weapon states to pursue verifiable disarmament, and presented its findings at the 2010 NPT Review Conference the 2012 NPT PrepCom, and the 2015 NPT Review Conference. [19]
Future Commitment
  • Prioritizes the negotiation of a verifiable Fissile Material Cut-Off Treaty (FMCT) without preconditions. The treaty should not cover existing stockpiles. [20]
  • Committed to reducing the existing nuclear weapons stockpile to less than 180 warheads by the mid-2020s. [21]


Trident II (D-5) Missile Underwater Launch, www.navy.mil

Nuclear Weapons Policies

  • Maintains the long-term goal of a world free of nuclear weapons and is viewed by many experts as the most successful nuclear weapon state in creating a minimum deterrent. [22] However, the government will continue its submarine-based ballistic missile nuclear deterrence capability as long as it feels is necessary given current global security considerations. The United Kingdom’s Ministry of Defence sees the large arsenals of certain states as reason to maintain a nuclear deterrent beyond the 2020s. [23]
  • Committed to reducing its arsenal size, but the UK is pursuing modernization of its warhead design, life extension of the Trident II D5 missiles, and a new SSBN fleet to replace the aging Vanguard submarines and maintain the CASD policy. [24] The new design SSBN will be powered with a PWR3 reactor and will maintain the nation’s nuclear deterrent into the 2060s. [25] The United Kingdom Ministry of Defence predicts that the first SSBN will be deployed in 2028. [26]
  • According to the Trident Alternatives Review issued in July 2013, replacing the current SSBN with an alternative strategic nuclear system such as placing nuclear warheads on cruise missiles would be more expensive than replacing with a direct successor SSBN fleet. [27]
  • The UK joined all other nuclear weapons possessing states in boycotting the 2017 Nuclear Ban Treaty negotiations at the UN General Assembly. The UK has no plans to join the Treaty. [28]
Nuclear Testing
Use of Nuclear Weapons
  • Maintains some ambiguity. Will "not rule in or out the first use of nuclear weapons." [33]
  • Has declared nuclear weapons will only be used in "extreme circumstances of self defence, including the defence of NATO allies," but remains "deliberately ambiguous" on the extent to which the country will use nuclear weapons in a time of crisis. [34] Will only use weapons in accordance with international law. [35]
  • Negative Security Assurances to Nuclear-Weapon-Free Zone (NWFZ) treaty members: Committed not to use nuclear weapons against members of the Tlatelolco, Rarotonga, and Pelindaba treaties by ratifying protocols of these treaties. [36] Will not use or threaten to use nuclear weapons against the non-nuclear weapon states of the NPT, conditional on their continued compliance with their nonproliferation obligations. [37]
  • As of June 2015, the United Kingdom, signed and ratified the Central Asian NWFZ protocols. [38] Agreed on language for the P5 Protocol to the SE Asian NWFZ (Bangkok Treaty), but postponed signing the treaty. Will make continued efforts to sign the protocol in the "near future." [39]
  • Acknowledged the commitments of the nuclear weapon states to negative security assurances in UN Security Council Resolution 984 (1995). [40]

Sources:
[1] Kelsey Davenport, "Nuclear Weapons: Who Has What at a Glance," Arms Control Association, 21 June 21 2018, www.armscontrol.org.
[2] Kelsey Davenport, "Nuclear Weapons: Who Has What at a Glance," Arms Control Association, 21 June 2018, www.armscontrol.org.
[3] "Arms Control and Proliferation Profile: The United Kingdom," Arms Control Association, 29 March 2017, www.armscontrol.org.
[4] U.K. Ministry of Defence, "2010 to 2015 Government Policy: UK Nuclear Deterrent," Policy Paper, 8 May 2015, www.gov.uk.
[5] “Dreadnought Class,” Royal Navy, www.royalnavy.mod.uk.
[6] Hans M. Kristensen and Robert S. Norris, "British Nuclear Forces, 2011," Bulletin of the Atomic Scientists, Vol. 67(5), pp. 89-97, 19 September 2011, www.thebulletin.org; John Ainslie, "United Kingdom: Status of UK's Nuclear Forces," in Assuring Destruction Forever publication by Reaching Critical Will, March 2012, www.reachingcriticalwill.org.
[7] John Ainslie, "United Kingdom: Status of UK's Nuclear Forces," in Assuring Destruction Forever publication by Reaching Critical Will, March 2012, www.reachingcriticalwill.org.
[8] Hans M. Kristensen, "U.S. Nuclear Weapons Withdrawn from the United Kingdom," Federation of American Scientists Strategic Security Blog, 26 June 2008, www.fas.org/blog/ssp; Robert S. Norris and Hans M. Kristensen, "Worldwide Deployments of Nuclear Weapons, 2009," Bulletin of the Atomic Scientists, Vol. 65(6), pp. 86-98, November 2009, www.thebulletin.org.
[9] Gareth Evans and Yoriko Kawaguchi, "Eliminating Nuclear Threat," Report of the International Commission on Nuclear Non-proliferation and Disarmament (ICNND), 2009, www.icnnd.org.
[10] Hans M. Kristensen and Robert S. Norris, "Status of World Nuclear Forces," Federation of American Scientists, June 2018, www.fas.org.
[11] Hans M. Kristensen and Robert S. Norris, "Status of World Nuclear Forces," Federation of American Scientists, June 2018, www.fas.org.
[12] Inventory of International Nonproliferation Organizations & Regimes, James Martin Center for Nonproliferation Studies, www.nonproliferation.org.
[13] U.K. Ministry of Defence, "2010 to 2015 Government Policy: UK Nuclear Deterrent," Policy Paper, 8 May 2015, www.gov.uk: "Nuclear Weapons: Who Has What at a Glance," Arms Control Association, April 2015, www.armscontrol.org.
[14] Robert S. Norris and Hans M. Kristensen, "Nuclear Pursuits, 2012," Bulletin of the Atomic Scientists, vol.68(1), pp. 94-98, www.thebulletin.org.
[15] "Main Committee I Statement," Report by Mr. Guy Pollard, Deputy Permanent Representative of the United Kingdom to the Conference on Disarmament, 2015 Review Conference of the Treaty on Non-Proliferation of Nuclear Weapons, 27 April - 22 May 2015.
[16] "The UK's Nuclear Deterrent: What You Need to Know," Defense Nuclear Organisation, February 19, 2018, www.gov.uk.
[17] "Britain discloses size of nuclear stockpile: Who's next?" Federation of American Scientists Strategic Security Blog, 26 May 2010, www.fas.org.
[18] "Main Committee I Statement," Report by Mr. Guy Pollard, Deputy Permanent Representative of the United Kingdom to the Conference on Disarmament, 2015 Review Conference of the Treaty on Non-Proliferation of Nuclear Weapons, 27 April - 22 May 2015.
[19] Ambassador Jo Adamson, Statement: Cluster I - Disarmament, 2012 Preparatory Committee for the Nuclear Non-Proliferation Treaty, 3 May 2012, www.reachingcriticalwill.org; United Kingdom Ministry of Defence, "The UK/Norway Initiative: report on the UKNI non nuclear weapon states workshop (7-9 December 2011)," www.gov.uk; "2015 Review Conference of the Parties to the Treaty on the Non-Proliferation of Nuclear Weapons: Main Committee 1," Statement by the Director of the Ministry of Foreign Affairs, Norway, 6 June 2015, www.norway-un.org.
[20] "Main Committee I Statement," Report by Mr. Guy Pollard, Deputy Permanent Representative of the United Kingdom to the Conference on Disarmament, 2015 Review Conference of the Treaty on Non-Proliferation of Nuclear Weapons, 27 April - 22 May 2015: Ambassador Joanne Adamson, Statement on Fissile Material Cutoff Treaty, Council of Disarmament, 12 March 2013, www.reachingcriticalwill.org.
[21] U.K. Ministry of Defence, "2010 to 2015 Government Policy: UK Nuclear Deterrent," Policy Paper, 8 May 2015, www.gov.uk.
[22] Secretary of State for Defence Dr. Liam Fox, "The United Kingdom's Future Nuclear Deterrent: The Submarine Initial Gate Parliamentary Report," May 2011, www.mod.uk.
[23] U.K. Ministry of Defence, "2010 to 2015 Government Policy: UK Nuclear Deterrent," Policy Paper, 8 May 2015, www.gov.uk.
[24] Secretary of State for Defence Dr. Liam Fox, "The United Kingdom's Future Nuclear Deterrent: The Submarine Initial Gate Parliamentary Report," May 2011, www.mod.uk; U.K. Ministry of Defence, "2010 to 2015 Government Policy: UK Nuclear Deterrent," Policy Paper, 8 May 2015, www.gov.uk.
[25] HM Government, Trident Alternative Reviews, 16 July 2013, www.gov.uk.
[26] U.K. Ministry of Defence, "2010 to 2015 Government Policy: UK Nuclear Deterrent," Policy Paper, 8 May 2015, www.gov.uk.
[27] Joseph Cirincione, Jon B. Wolfsthal, Miriam Rajkumar, "United Kingdom," in Deadly Arsenals (Washington, D.C.: Carnegie Endowment for International Peace, 2005), pp. 197-201.
[28] “Positions on the treaty,” International Campaign to Abolish Nuclear Weapons, 7 July 2017, www.icanw.org.
[29] CTBTO Preparatory Commission, "Status of Signature and Ratification," accessed 4 August 2014, www.ctbto.org.
[30] United Nations Office of Disarmament Affairs, "Treaty Banning Nuclear Weapons Tests in the Atmosphere, in Outer Space and Under Water," https://disarmament.un.org.
[31] "Main Committee I Statement," Report by Mr. Guy Pollard, Deputy Permanent Representative of the United Kingdom to the Conference on Disarmament, 2015 Review Conference of the Treaty on Non-Proliferation of Nuclear Weapons, 27 April - 22 May 2015.
[32] The Future of the United Kingdom's Nuclear Deterrent: Defence White Paper 2006, Secretary of State for Defence and The Secretary of State for Foreign and Commonwealth Affairs, December 2006, www.fas.org.
[33] Policy Paper: 2010 to 2015 Government Policy: UK Nuclear Deterrent, Ministry of Defence, updated on 8 May 2015, www.gov.uk.
[34] International Organizations and Nonproliferation Program (IONP), "Nuclear Weapon Free Zone (NWFZ) Clearinghouse," James Martin Center for Nonproliferation Studies, www.nonproliferation.org.
[35] "Main Committee I Statement," Report by Mr. Guy Pollard, Deputy Permanent Representative of the United Kingdom to the Conference on Disarmament, 2015 Review Conference of the Treaty on Non-Proliferation of Nuclear Weapons, 27 April - 22 May 2015.
[36] Ambassador Joanne Adamson, Statement: Cluster II - Non-Proliferation, 2012 Preparatory Committee for the Nuclear Non-Proliferation Treaty, 7 May 2012, www.reachingcriticalwill.org; Shubhra Chaturvedi, "Southeast Asian Nuclear Weapon Free Zone Treaty: What's Holding It Up?" International Peace and Conflict Studies, 31 July 2012, www.ipcs.org.
[37] "Main Committee I Statement," Report by Mr. Guy Pollard, Deputy Permanent Representative of the United Kingdom to the Conference on Disarmament, 2015 Review Conference of the Treaty on Non-Proliferation of Nuclear Weapons, 27 April - 22 May 2015.
[38] "Main Committee I Statement," Report by Mr. Guy Pollard, Deputy Permanent Representative of the United Kingdom to the Conference on Disarmament, 2015 Review Conference of the Treaty on Non-Proliferation of Nuclear Weapons, 27 April - 22 May 2015.
[39] Ambassador Matthew Rowland, Cluster 1 Issues Statement to the 2014 NPT Preparatory Committee, 2 May 2014. www.reachingcriticalwill.org; "Main Committee I Statement," Report by Mr. Guy Pollard, Deputy Permanent Representative of the United Kingdom to the Conference on Disarmament, 2015 Review Conference of the Treaty on Non-Proliferation of Nuclear Weapons, 27 April - 22 May 2015.
[40] Beatrice Fihn, "The Conference on Disarmament and NSAs," UNIDIR, March 2011, www.unidir.org.

January 2, 2019
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The Nuclear Disarmament Resource Collection contains information and analysis of nuclear weapons disarmament proposals and progress worldwide, including detailed coverage of disarmament progress in countries who either possess or host other countries' nuclear weapons on their territories.

This material is produced independently for NTI by the James Martin Center for Nonproliferation Studies at the Middlebury Institute of International Studies at Monterey and does not necessarily reflect the opinions of and has not been independently verified by NTI or its directors, officers, employees, or agents. Copyright 2019.