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How Will the Labour Party Shape UK Nuclear Weapons Policy?
December 2024
By Sebastian Brixey-Williams
UK Prime Minister Kier Starmer’s Labour Party has signaled its “unshakeable” and “absolute” commitment to nuclear deterrence after sweeping to power in the United Kingdom in July.
After 14 years of Conservative Party-led government, voters handed Starmer’s party a landslide victory on par with Prime Minister Tony Blair in 1997. Bolstered by an overwhelming majority of members of Parliament, Labour now has the mandate to make ambitious policy change across government. The public will see what that means for nuclear policy when the Strategic Defence Review is released early in 2025.
The review will be headed by Lord George Robertson, reporting to Defence Minister John Healey. Robertson is a Labour defense policy veteran, having served as defense minister in 1997-1999 before becoming NATO secretary-general in 1999-2003. He will work alongside Fiona Hill, a former U.S. National Security Council official, and Richard Barrons, a retired army general and former commander of the UK Joint Forces Command.
The review must articulate Labour’s approach to nuclear weapons policy at a moment of profound international upheaval: the full-scale war against Ukraine waged by Russia; growing violence in the Middle East involving nuclear-armed Israel, which may drive Iran to nuclearize further; ongoing uncertainty about the relationship between China and the West; and growing disquiet about the erosion of the multilateral nonproliferation and disarmament regime. Within this darkening context, how might Labour demonstrate accountable leadership on nuclear weapons policy?
By extending a strong tradition of forward-leaning Labour policy, there are several concrete ways that the new government can demonstrate its commitment to reduce nuclear weapons risks and harms and advance the multilateral disarmament agenda, while signaling Labour’s seriousness about defense and security. To do this, Labour should demonstrate that responsibility, accountability, transparency, and international law are the bedrock principles of the UK nuclear weapons program.
Progressive Opportunities
The review team should start by revisiting the in-depth introspective work done by the civil service on UK nuclear responsibilities with respect to its nuclear weapons, partners, adversaries, and the wider international community. Working through frameworks such as BASIC’s Responsibilities Framework1 has proven a valuable starting point for building shared understanding across government of UK obligations and duties, and much of this prior work still has relevance.
Yet, the review process also should explore whether the UK can reverse the Prime Minister Boris Johnson-era policy of secrecy and return to publicly releasing numbers on the operational stockpile and deployed warheads and missiles. This move would restore confidence in the UK commitment to the principle of transparency, signal its willingness to contribute responsibly to arms control and disarmament dialogue, and remove an excuse for other nuclear-armed states not to behave similarly. It also would signal an important break from the recent UK turn toward rearmament. UK nuclear forces were on a gradual downward trend under successive Conservative governments, with the 2010 strategic review announcing a planned inventory reduction from “not more than 225 to not more than 180” warheads.2 Surprising many observers, the 2021 review increased the cap on warhead numbers from 225 to “no more than” 260. This change was reported widely as a 40 percent increase, based on the 180 figure, even though the actual change may well be narrower.
In another departure from precedent, the 2021 review announced that the government would “no longer give public figures for [the] operational stockpile, deployed warhead or deployed missile numbers,” deepening UK nuclear opacity.3 Yet France, which has a similar-sized nuclear arsenal, does make such information available, and restarting data releases would match the U.S. decision to return to declassifications earlier this year.4 Such a move would strengthen international norms of transparency and accountability and set clear standards for other nuclear-armed states to follow.
Labour also should explore whether the UK can provide greater transparency on nuclear doctrine, with the purpose of making the case to domestic and international audiences about the lawfulness and ethics of its employment policy. There is an incompatibility between the UK “commitment to transparency of doctrine and capability”5 and the policy of being “deliberately ambiguous about precisely when, how, and at what scale” the government would use the weapons.6 This does not mean that Labour needs to start listing target sets publicly, in a manner that could risk national security or be misinterpreted as nuclear threats. Instead, Labour should revive the spirit of elaborating UK nuclear deterrence philosophy as exemplified in a 1980 defense document, which clarified that the state’s nuclear weapons were intended to pose a “potential threat to key aspects of Soviet state power”7 rather than, as its probable author Michael Quinlan later explained, “crude counter-city or counter-population concepts.”8 Nearly half a century later, Labour should reaffirm this principle and explore how to exclude publicly certain varieties of target to signal its compliance with international humanitarian and environmental legal obligations. If this was possible during the Cold War, it should be possible now.
Embracing International Law
Building on this, the UK should commit to updating and expanding its understanding of how international law applies to nuclear weapons targeting. This move has precedent, but the last detailed official document on the subject is the UK’s 1995 statement to the International Court of Justice.9 Customary international law and popular understanding of the effects of nuclear weapons have evolved in significant ways since then. The UK should commit in the new review to articulating in more detail how the principles of distinction, proportionality, and precaution in attack under international humanitarian law would apply to nuclear targeting and the kinds of legal tests that must be met for 100-kiloton UK weapons to be used lawfully. Being transparent about such advice is essential to accountability and especially important when it comes to highly contested legal questions, such as whether belligerent reprisals against civilians populations are lawful.
Labour also should elaborate the internal processes by which the Ministry of Defence determines lawfulness, for instance by explaining the role that legal advisers play in screening nuclear targeting plans; the kind of legal advice that prime ministers receive upon entering office while writing their “letter of last resort,” which provides the final orders to Royal Navy ballistic missile submarine commanders in the event that London is believed destroyed; and the way in which legal advice is integrated with nuclear decision-making during crises. Now led by Starmer, a former director of public prosecutions who has campaigned on a platform of integrity and accountability, the government has an opportunity to provide greater confidence that UK nuclear targeting is fully compliant with its legal obligations by clearly articulating its understanding of the law and reaffirming the authority of international law in nuclear targeting more generally.
It is critical too that Labour restore and nourish legislative oversight of nuclear modernization programs, which has diminished dramatically as key members departed Parliament and the public and the media lost interest. The closure this year of the All-Party Parliamentary Group on Global Security and Non-proliferation following dwindling attendance and funding exemplified this trend.10 Labour should replenish the stocks of parliamentarians who consider nuclear weapons policy to be part of their issue brief by grooming and training new members of Parliament and peers of all political parties, with the support of experts countrywide. The government should restart the annual updates to Parliament on the future UK nuclear deterrent, which unexpectedly stopped after 2022.
Labour should launch a comprehensive public inquiry into historic UK nuclear weapons harms to establish whether the UK has caused humanitarian, environmental, or social harms in developing and sustaining its nuclear program and take steps to mitigate or redress these harms where necessary. Harms should be understood broadly, covering the full life cycle of nuclear weapons production, including uranium mining, testing, and the displacement of populations. Those leading the inquiry should engage widely with officials and military officers, lawyers, anthropologists, scientific experts, and affected communities during the investigation. If warranted, the inquiry should produce recommendations for restorative or reparatory justice mechanisms.
Finally, Labour should invest in the UK as an incubator for innovative, practical measures toward multilateral reductions in nuclear weapons. The UK has done detailed work on nuclear disarmament verification and irreversibility in recent years. In addition to building on these foundations, Labour should be more ambitious by reviving and adapting the concept outlined in 2007 by Labour Foreign Secretary Margarett Beckett of positioning the UK as a “disarmament laboratory.”11 Now that the Defence Ministry has established a nuclear deterrence fund, the government should increase spending for new research and diplomatic initiatives on risk reduction, arms control, and disarmament. At this critical juncture, the UK should demonstrate that a world without nuclear weapons is in its vital interests and publicly signal a willingness to be included, under certain conditions, in future multilateral arms control reductions talks.
Labour’s Nuclear Inheritance
These and other recommendations will need to overcome two challenges in UK nuclear politics. First, political attention is directed primarily toward ensuring the viability of UK nuclear deterrence because of the significant programmatic challenges that Labour has inherited and the perception that the country’s adversaries and competitors are placing new strategic demands on it.
The existing Vanguard ballistic missile submarine program is in poor shape. Submarine sea patrols, previously no more than three months, are being forced to remain at sea for as many as six months due to spiraling repairs and reported challenges in recruiting crew.12 In 2022, one of the four UK submarines finally returned to service from a refit that was extended from four years to seven after the scope was expanded beyond the original plans and failures in workforce and infrastructure investments. During the extra three years that the HMS Vanguard was in dry dock, the Royal Navy was forced to try to maintain its mission of keeping at least one submarine at sea at all times while at times missing 25 to 50 percent of its operational submarine fleet. Major questions remain on whether the submarine replacement program Dreadnought will meet its deadline for having the first boat enter service in the early 2030s.13 Labour must be careful about its messaging to avoid being blamed for operational, budgetary, or procurement failures that preceded its mandate.
Labour also inherits a nuclear warhead modernization program at a critical juncture, the Astraea. Although promoted as a “sovereign design,” this warhead is being “delivered in parallel with” the U.S. W93 warhead.14 The name of the UK warhead was carefully calibrated: Astraea is named after the Roman goddess of justice and, according to some sources, innocence, purity, and precision. In some depictions, she fittingly carries a thunderbolt of justice and was said by the epic poet Hesiod to have been the last deity to leave the earth during the evil days of the Bronze Age, when warlike men were consumed by their own rage and perished.15 The most recent program update to Parliament in 2022 stated that the warhead had moved into the concept phase, but little more is known about the program. David Cullen, executive director of the watchdog Nuclear Information Service, has reasoned that the “technological dependency of the UK nuclear weapons program on the United States means that the UK Replacement Warhead is likely to have a similar design to the W93, and may therefore produce a significantly higher yield than the current UK warhead.”16 If true, this raises important questions as to whether the UK modernization plans are geared more toward like-for-like replacement or a capability change.
Starmer’s government also may have inherited a country poised for U.S. forward deployments. Although not mentioned in the 2021 review, the Federation of the American Scientists, citing a vague U.S. budget reference, reported in 2023 the possibility that RAF Lakenheath is being readied again as a base for U.S. nuclear weapons.17 London has declined to comment on this report, but there are plausible reasons why it might be true. With U.S. attention increasingly focused on China, the UK appears to be taking on a greater share of the responsibility for NATO’s nuclear deterrence against Russia. This will be especially true under the second Trump administration, whose attention will be on China and will call for European allies to take greater responsibility for their own defense.
London also may be concerned about its lack of substrategic options compared to Russia. Although it is commonly assumed that the UK still has the capacity to deploy a low-yield variant of its Holbrook warhead, it is difficult to imagine that more than one or two missiles per boat would be dedicated to this variant or that they would be used readily because their use simultaneously would locate the UK’s second-strike capability. U.S. forward deployments might provide a cost-efficient alternative to developing a U.S. low-yield nuclear capability, for instance by reestablishing a Royal Air Force nuclear capability or arming Royal Navy attack submarines with nuclear-tipped cruise missiles. Such basing also would put another bargaining chip on the table for any longer-term European arms control and demilitarization. In essence, NATO could attempt to trade U.S. weapons at Lakenheath for Russian weapons in Belarus without fundamentally changing the remaining balance of nuclear, missile defense, or other forces in Europe.
The increase to the UK warhead cap, London’s rollback in transparency measures, and the credible possibility of U.S. forward deployments have ended an extended period of complacency about the irreversibility of UK disarmament progress and demonstrated that the civil service is not locked into a linear course toward nuclear elimination. Although the new leaders undertaking the Strategic Defence Review are well-informed, the process will be advised by an entrenched cadre of civil servants, which will surely influence Labour’s nuclear weapons policy. The strategic context in Europe has changed dramatically since the 2022 full-scale Russian invasion of Ukraine, meaning further increases to the UK warhead cap or even the adoption of new capabilities should not come as a surprise.
Starmer’s Opening Position
The second key challenge is that the diminished space for democratic debate on UK nuclear politics is now led from the top of the Labour Party itself. Starmer came out swinging in his election campaign to dispel any allegation that the party is “weak on defence,” a deep-rooted association that has been an Achilles heel in Labour’s domestic policy platform for decades. Indeed, Starmer’s “unshakeable” and “absolute” commitment to nuclear deterrence is stauncher than any recent Labour leader. Contrast this to the equivocal, almost flippant position taken by former Prime Minister Blair in his memoir on the Trident renewal decision in 2006: “[A]fter some genuine consideration and reconsideration, I opted to renew.… I said to [Gordon Brown]: imagine standing up in the House of Commons and saying I’ve decided to scrap it. We’re not going to say that, are we?”18
At the top of Starmer’s mind will be closing off any comparison with his predecessor, Jeremy Corbyn, who ran on a divisive platform advocating pacifism and unilateral nuclear disarmament and later was mired in anti-Semitism allegations. Corbyn’s public refusal to “push the button,” however noble in its intention, undoubtedly harmed Labour’s electability.19 Formerly in Corbyn’s shadow cabinet, Starmer is doing everything he can to sever any association with his predecessor and depoliticize nuclear weapons for his government so it can focus on the country’s myriad domestic challenges.
Eliminating any doubt about Starmer’s commitment to a “triple lock” on the nuclear deterrent,20 the government’s first major public act has been the extension of the UK-U.S. Mutual Defence Agreement. This included the permanent removal of the need to renew the key clause on the transfer of materials and equipment every 10 years,21 further embedding cooperation and eliminating a substantial risk to the continuity of the UK nuclear program. Although the allies still may review minor technical updates to the agreement, this major indefinite extension decision will deprive elected officials in both countries of the opportunity to revisit the more fundamental principle of whether to share nuclear materials and equipment in future years.
Indeed, Starmer is under little political pressure to concede ground on disarmament. The near-total electoral collapse of the Scottish National Party, having nosedived from 49 to 9 seats in Scotland’s 57 constituencies, looks to have weakened permanently efforts toward a second Scottish independence referendum and unilateral nuclear disarmament in the UK. Only a few years ago, Scottish independence appeared to be the most likely route to a unilaterally disarmed UK, given the immense practical, legal, and financial difficulties of relocating the nuclear submarine base to one of the few deepwater ports elsewhere in the country.22 Not so today.
Although Starmer’s opening statements have been forthrightly pro-nuclear, Labour ultimately may soften its approach. Evidence of this can be seen in the foreign policy philosophy set out by Foreign Secretary David Lammy, who has campaigned as a “progressive realist” with hopes to weave together elements of an “ethical foreign policy” espoused by the late Foreign Secretary Robin Cook with “tough on defence” pragmatism.23 The message is one of continuity with a difference: an approach to defense and security that is framed as strong and serious, but differentiated from its predecessors through its greater moral sensibility. The government is not short of international security or foreign policy decisions by which Lammy’s vision can be tested.
As the strategic review gets underway, Starmer’s government must find its own way to grapple with the conflicting UK policy commitments toward deterrence and disarmament. Domestic political pressures, limited parliamentary capacity, and an unstable international environment make reductions to the UK arsenal improbable; they may even reverse further. Yet, nearly two decades on, Beckett’s words are as true today as they were in 2007; and Labour would do well to recall them: “The judgement we made forty years ago, that the eventual abolition of nuclear weapons was in all of our interests - is just as true today as it was then. For more than sixty years, good management and good fortune have meant that nuclear arsenals have not been used. But we cannot rely on history just to repeat itself.”24
ENDNOTES
1. Sebastian Brixey-Williams, Alice Spilman, and Nicholas J. Wheeler, “The Nuclear Responsibilities Toolkit: A Practical Guide for Thinking, Talking and Writing,” British American Security Information Council (BASIC) and Institute for Conflict, Cooperation and Security, September 2021, p. 25, https://basicint.org/wp-content/uploads/2022/01/BASIC_Nuclear-Responsibilities-Toolkit_2nd-Edition.pdf.
2. “Securing Britain in an Age of Uncertainty: The Strategic Defence and Security Review,”
Cm 7948, October 2010, p. 39.
3. The Campaign for Nuclear Disarmament commissioned a legal advice that sought to challenge the lawfulness of the buildup, which concluded that the “announcement by the UK government of the increase in nuclear warheads and its modernisation of its weapons system constitutes a breach of the [nuclear Nonproliferation Treaty Article] VI,” but puzzlingly it stopped short of litigating the decision in the courts. Christine Chinkin and Louise Arimatsu, “ Legality Under International Law of the United Kingdom’s Nuclear Policy as Set Out in the 2021 Integrated Review,” Campaign for Nuclear Disarmament (CND), April 2021, https://cnduk.org/wp-content/uploads/2021/05/CND-legal-opinion-1.pdf.
4. U.S. National Nuclear Security Administration, “Transparency in the U.S. Nuclear Weapons Stockpile,” n.d., https://www.state.gov/wp-content/uploads/2024/07/U.S.-Nuclear-Weapons-Stockpile-Transparency-2024_2.pdf (data as of September 2023).
5. 2020 Review Conference of the Parties to the Treaty on the Non-Proliferation of Nuclear Weapons, “National Report of the United Kingdom of Great Britain and Northern Ireland Pursuant to Actions 5, 20 and 21 of the Action Plan of the 2010 Review Conference of the Parties to the Treaty on the Non-Proliferation of Nuclear Weapons for the Tenth Review Conference of the Parties to the Treaty,” NPT/CONF.2020/33, November 5, 2021, p. 33.
6. UK Defence Nuclear Organisation, “The UK’s Nuclear Deterrent: What You Need to Know,” n.d., https://www.gov.uk/government/publications/uk-nuclear-deterrence-factsheet/uk-nuclear-deterrence-what-you-need-to-know (accessed November 17, 2024).
7. UK Ministry of Defence, “The Future United Kingdom Strategic Nuclear Deterrent Force,” Doc. 80/23, July 1980, para. 12, https://nsarchive.gwu.edu/sites/default/files/documents/qw8t8k-z13mv/34.pdf.
8. Michael Quinlan, Thinking About Nuclear Weapons: Principles, Problems, Prospects (Oxford: Oxford University Press, 2009), p. 126.
9. UK Foreign and Commonwealth Office, “Legality of the Threat or Use of Nuclear Weapons (Request for an Advisory Opinion by the United Nations General Assembly): Statement of the Government of the United Kingdom,” June 1995, https://www.icj-cij.org/sites/default/files/case-related/95/8802.pdf.
10. Sebastian Brixey-Williams, “APPG on Global Security and Non-Proliferation to Close After 24 Years,” May 14, 2024, https://basicint.org/appg-to-close-after-24-years/.
11. “Keynote Address: A World Free of Nuclear Weapons?” Carnegie Endowment for International Peace, June 25, 2007, https://carnegieendowment.org/events/2007/06/keynote-address-a-world-free-of-nuclear-weapons (remarks of Margaret Beckett) (hereinafter Beckett address).
12. CND, “Royal Navy Struggles to Attract Recruits for Nuclear-Armed Subs,” June 19, 2023, https://cnduk.org/royal-navy-struggles-to-attract-recruits-for-nuclear-armed-subs/.
13. Toby Fenwick, “(Dis)Continuous Deterrence: Challenges to Britain’s Nuclear Doctrine,” BASIC, September 2018, https://basicint.org/wp-content/uploads/2018/11/DisContinuous-Deterrence-Web.pdf.
14. UK Defence Nuclear Enterprise, “Delivering the UK’s Nuclear Deterrent as a National Endeavour,” CP 1058, March 2024.
15. “Astraea,” Oxford Reference, n.d., https://www.oxfordreference.com/display/10.1093/oi/authority.20110803095430649 (accessed November 17, 2024).
16. David Cullen, “Extreme Circumstances: The UK’s New Nuclear Warhead in Context,” Nuclear Information Service, August 2022, p. 49, https://www.nuclearinfo.org/wp-content/uploads/2022/08/Extreme-Circumstances-print-version.pdf.
17. Matt Korda and Hans Kristensen, “Increasing Evidence That the US Air Force’s Nuclear Mission May Be Returning to UK Soil,” Federation of American Scientists, August 28, 2023, https://fas.org/publication/increasing-evidence-that-the-us-air-forces-nuclear-mission-may-be-returning-to-uk-soil/.
18. “Blair on Trident: ‘There Was a Case Either Way,”’ Nuclear Information Service, March 9, 2010, https://www.nuclearinfo.org/blog/nuclear-information-service/2010/09/blair-trident-there-was-case-either-way/.
19. Patrick Wintour, “Jeremy Corbyn: I Would Never Use Nuclear Weapons If I Were PM,” The Guardian, September 30, 2015, https://www.theguardian.com/politics/2015/sep/30/corbyn-i-would-never-use-nuclear-weapons-if-i-was-pm.
20. Nick Ritchie, “Keir Starmer’s Trident Triple Lock: How Britain’s Obsession With Nuclear Weapons Has Become Part of Election Campaigns,” The Conversation, June 6, 2024, http://theconversation.com/keir-starmers-trident-triple-lock-how-britains-obsession-with-nuclear-weapons-has-become-part-of-election-campaigns-231834.
21. UK Secretary of State for Foreign, Commonwealth and Development Affairs, “Amendment to the Agreement Between the Government of the United Kingdom of Great Britain and Northern Ireland and the Government of the United States of America for Cooperation on the Uses of Atomic Energy for Mutual Defense Purposes,” CP 1135, July 2024.
22. Sebastian Brixey-Williams, “Voting for Trident Before the Scotland Question Is Settled Is Illogical,” BASIC, July 18, 2016, https://basicint.org/news/2016/voting-trident-scotland-question-settled-illogical.
23. “A Friend of Obama Who Could Soon Share the World Stage With Trump,” The New York Times, April 21, 2024.
Sebastian Brixey-Williams is executive director of BASIC, a think tank, and a research fellow at the Harvard Kennedy School Project on Managing the Atom.