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The case for new nukes
In which I argue for British air-launched cruise missiles.
As we stand by for the MoD’s new/revised Command paper, I recently made the case that the UK should re-establish a second ‘leg’ of its nuclear deterrent. Why? Read on… bearing in mind there is nothing secret in what follows.1
A Vanguard class submarine of the Royal Navy leaving port
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The argument for establishing a second mode of nuclear weapon delivery depends on an assessment of risk. There is no exact science of deterrence, which is primarily a matter psychological judgement.
But on the basis of the analysis below, I conclude that: the current minimal deterrent, resting on one continuously deployed SSBN, is insufficiently robust.
This is because:
1. Technological advances threaten the security of the SSBN, and the UK’s retaliatory capability.
2. The reliability of the US alliance – including its extended deterrence via NATO and its essential material contributions to UK capabilities – cannot be assumed.
3. Challenges at the upper end of the conventional and lower end of the nuclear spectrum probably cannot be credibly deterred by the existing UK force structure.
4. Public support for the Dreadnought class SSBN cannot be assumed for its anticipated in-service life.
The remainder of this piece unpicks these contentions (Part A), before outlining some options for the deterrent (Part B). Ultimately, I argue for the acquisition of air launched cruise missiles as the most effective addition to the deterrent force. So when I say ‘new nukes’ - I really mean new delivery systems (which will also entail new warheads).
Part A. The rationale for an additional nuclear option
1. Technology developments
Submarines are hard to detect and continue to offer the most reliable means of assuring a retaliatory capability. The Royal Navy has successfully maintained a continuous nuclear patrol for half a century, despite a small margin for error.2
Over the years, there has been extensive discussion of the prospects for detecting the SSBN, but no public evidence that this is yet a realistic proposition.3 However, no other nuclear power relies solely on submarine delivered nuclear weapons, making the UK uniquely vulnerable to any change in this situation.
Will it change? There is considerable ongoing research on sensor technologies that could detect signals emitted by submarines – including in the acoustic and electro-magnetic spectrums. Much of this research is highly technical and classified, making open-source, lay appraisals difficult. The signals involved are often small, relative to the scale of the ocean and the amount of background noise. Evidently, creating sufficiently numerous, robust and sensitive sensors continues to be a formidable obstacle to practical submarine detection.
But changes are coming that may permit much larger sensor networks, more powerful sensors, and improved data analysis. One key threat to the status quo comes from the development of computer technologies, notably rising processing power (with the most powerful HPC clusters now exceeding one teraflop and the imminent arrival of practical quantum machines); and the very rapid development of powerful machine learning techniques, especially via transformer networks conducting unsupervised learning in very large datasets. Together, these developments will permit the collection and analysis of data about the ocean on a scale hitherto inconceivable.
At sea, expect the development of cheap and powerful processing power ‘at the edge’ – that is aboard sensor platforms – including energy efficient neuromorphic chipsets. Additionally, expect the development of very large, distributed networks of uncrewed platforms in a variety of types – ranging from recoverable vessels along the lines of modern SSNs and SSKs, through XLUUVs (Orca, Manta etc), down to smaller sensors akin to today’s hydrophone networks, but available on unprecedented scale. These latter might be sufficiently cheap to be effectively disposable and could even be mobile – operating as a shoal. Ashore, expect improvements in data analysis and modelling, via the instantiation of extremely large High Performance Computers and their integration in hybrid systems with quantum computing machines.
Collectively, these new nodes and analytical processes exploit key advantages of modern computing. The SSBN detection problem amounts to finding needles in haystacks, but AI in recent years has proved very adept at exactly this problem: search and pattern recognition in large, noisy datasets. The SSBN is a single, centralised platform in an era that will increasingly favour, distribution, mass and autonomy.
Among the additional factors to consider: geography will continue to favour the UK, with a relatively short run from its home port to the noisy, difficult to surveil polar patrol area. Maintaining large, distributed networks of sensors will be a challenge for China and Russia, the UK’s most likely potential adversaries, operating far from their own home ports. Conversely, the lingering possibility of Scotland’s secession raises the risk of active tracking as boats leave more exposed English ports.
2. The reliability of the US alliance.
Since the Manhattan project, the British nuclear programme has been closely linked to that of the US. Tensions have ensued – the post-War McMahon Act restricted access to US know-how, spurring the development of indigenous British capabilities. One of these, the Blue Streak missile, failed, leaving the UK reliant on American missile technology. When the Americans abruptly cancelled their own Skybolt programme, the British deterrent was at risk. A compromise deal gave the UK access to the Polaris SLBM, albeit that this was ostensibly earmarked for NATO use (naturally, the UK interpreted the deal differently).4 Later, President Reagan’s determination to press ahead with ballistic missile defences caused considerable unease in Whitehall, given the prospect that such technologies might undermine the effectiveness of ballistic missiles, even of Britain’s recently MIRV’d Polaris.5
Matters calmed thereafter, and the UK had already acquired the US Trident missiles whose successors remain in use. But the lesson remained – the deterrent is operationally independent, but the British-owned missiles are maintained by the US, in the US, and held as part of a common pool. Sustainment of UK’s operationally independent deterrent depends then as now on the strategic choices of the United States. This dependency is demonstrated by the UK’s lobbying for a new US warhead, the W93, which might be the basis of our own future warhead design.6
The geostrategic interests of the US and UK are often, but not always, in alignment. From the creation of Israel, the abortive Franco-British action in Suez, through the post-Cold War tensions over ‘lift and strike’ in Bosnia, popular opposition in the UK to the Iraq war, and on to the Biden administration’s abrupt withdrawal from Afghanistan – there have been many foreign policy disagreements. There is undoubtedly, however, much shared history, and very often there is common interest, as amply demonstrated in ongoing support for Ukraine. At its core, the relationship is founded on a deep and enduring commitment to the security of the Euro-Atlantic area.
But there are reasons to suggest that the longstanding amity should not be taken entirely for granted. The recent Trump administration gave a startling demonstration of the potential for divergence. In his attitude to authoritarian powers – including Russia and North Korea, Trump departed from long established positions and norms of international behaviour. His attitude to NATO had elements of continuity (that Europe needs to spend more money on defence7) and change (repeatedly making favourable comments about Putin, privately contemplating leaving NATO8, and even suggesting that America would not come to allies’ aid in the event of attack9).
Trump may be a unique character, but the fault lines in American politics run deeper than his personality, so that the established foreign policy positions of the last 80 years cannot be taken for granted, notwithstanding the return to the norm under President Biden. Events in Washington DC of 6th January 2020 illustrated stark fissures in US civil society and the fragility of its democracy. Over recent decades, the Republican party has progressively departed from the broadly bipartisan foreign policy consensus, and come to represent populist themes including nativism, neo-isolationism and unilateralism. These changes are driven in part by profound demographic and socio-economic changes, and perhaps catalysed by new and polarising social media technologies. There is little reason to suppose that they will melt away after Trump and, anyway, every possibility that he will return to office.
Meanwhile, the UK has the longstanding habit of operating alongside, or in coordination with the US in the conventional deployment of force. This habit has shaped its military concepts, equipment and attitudes. It has fostered an expectation within Britain’s armed forces that Anglo-American partnership is permanently hardwired into the national security ecosystem – and moreover that the British, perhaps uniquely among its allies, are as operationally capable as American forces. The sentiment is evidently not shared by some American counterparts.10 But they are shared by British society more broadly. Here, a powerful nostalgia for the Second World War and an ongoing Euroscepticism together shape public discourse on national security, alongside more recent, living memories of shared endeavour in Iraq, Afghanistan and Syria. The Special Relationship remains a powerful and lasting bond, but may mask the extent to which changes in America are shifting the tectonic plates of Euro-Atlantic security.
3. Challenges at the lower end of the nuclear spectrum are coming
The nuclear taboo is robust. But that should not be taken for granted. In recent years, the chemical weapons taboo has been violated by Syria’s President Assad, a close Russian ally, with few consequences, despite the declaration by President Obama of a ‘red line’. The nuclear taboo may be similarly eroded, for example, by the detonation of a radiological device and by nuclear responses to it. In late 2022, Russia’s defence minister suggested that Ukraine planned such a detonation, in what looked suspiciously like a false-flag operation.11 That sort of disinformation echoes the deliberately muddled Syrian experience. Meanwhile, numerous Russian actors have made nuclear threats in response to NATO support for Ukraine. As Russia comes under increasing military pressure in Ukraine, deliberate or accidental detonation of a nuclear weapon becomes at least conceivable. What then?
The UK can realistically expect not to face the problem of nuclear use in this or similar contexts alone (that is, of nuclear attacks on its non-nuclear allies). But what if nuclear allies disagreed on the appropriate response, or even ruled out nuclear retaliation ex ante, as did France’s President Macron in the Ukraine context?12 The UK’s current ability to unilaterally deter this sort of challenge is limited by the inflexibility of its response (either a relatively small-scale conventional deployment, or the use of Trident missiles, whose pre-set warhead yield could not be determined by any adversary, even if the intention was a limited response).
Meanwhile, other nuclear actors are developing increasingly flexible, layered deterrent systems. These include the use of ballistic missiles for conventional payloads and warfighting (as with China’s anti-ship missiles, the DF-21D and DF-26). There are also new nuclear-capable systems, including hypersonic glide vehicles, and uncrewed submersibles, like Russia’s nuclear-powered Poseidon. The US continues to mature its ABM system and to roll out a larger long-range bomber capability, via the new B-21 Raider. On the horizon are further developments, including some that draw on autonomy to permit mass and speed at unprecedented levels. Together, these new weapons and the command systems that integrate them will complicate adversary calculations. Hopefully in so doing they will inculcate caution and so promote stability. With more nuclear options come increased challenges of control, but also more second-strike assurance, and so more retaliatory credibility.
4. Public attitudes may turn against the continuation of Dreadnought and/or the deterrent itself.
The nuclear deterrent does not feature prominently in public discourse, even when the focus is more narrowly on national security. One recent survey, conducted by Pugwash in early 2023, well after Russia’s invasion of Ukraine, found the UK public broadly split on key issues – for example with 48% opposing ‘first use’ (British policy does not rule that out).13 On possession of the deterrent, 40% favoured and 27% opposed – but a substantial 34% were either undecided or didn’t know. This uncertainty on central questions about nuclear weapons indicates a degree of public disengagement and perhaps ambivalence. It suggests that continued public support for nuclear weapons cannot be presumed.
The current deterrent is already expensive, with operating costs of some £3bn pa; developing its replacement is expected to cost between £31bn and £41bn.14 There are many other worthy calls on the Exchequer. There was little public debate about SSBN renewal, but no guarantee that situation will hold over the 25-plus years of their anticipated service life. Fully 39% of respondents to the 2023 Pugwash survey favoured joining the Treaty on the Prohibition of Nuclear Weapons, with support particularly strong amongst the under 35s. That Treaty prohibits possession and acquisition of new nuclear weapons. Conversely, however, the expansion of the UK’s warhead pool, announced in 2021, aroused little public debate. And support for the deterrent had grown since an earlier Pugwash survey conducted before Russia’s invasion. Overall, then, ambivalence seems the order of the day.
Expanding the deterrent beyond what’s already planned could prove controversial for a public unversed in the nuance of strategic theory. To do so, the UK government would have to hope that opposition remains limited. Mounting an explicit argument that the expansion will ameliorate the risks of improved SSBN detection might undercut the rationale for Dreadnought. And mounting a public argument that the extra delivery system will offset exposure to American decision-making seems geopolitically improbable. Public sentiment remains warm towards the American people, but markedly cooler towards their political leaders – especially during the Trump Presidency.15 Perhaps, then, the best approach would be to point to increased global instability, and nod to the threat posed by new technologies under development elsewhere, like China’s hypersonic programme.
B. Options for an additional nuclear option:
There are three possible options for an alternative delivery mechanism:
1. Restoring the gravity bomb capability that the UK withdrew in 1998.
This option might prove the cheapest means of diversifying the UK deterrent. It would, however, also offer the least reliable means of delivery. The range to likely targets contrasts with the limited endurance of the UK’s current and projected strike aircraft; while both the aircraft and its carrier are vulnerable to missile attack, particularly when operating close to enemy shores or in areas with sophisticated integrated air defences.
One alternative option might be to acquire the new US B-21 long range bomber – but this might not be released for export, would be costly (at some $700m per aircraft), and anyway would not ameliorate the other concern raised here – the ongoing reliance on the US for our sovereign deterrent.
2. Developing a new submarine launched cruise missile
This option would give the UK the ability to launch from more platforms, including from its SSNs. But it would risk escalation in the event of using SLCMs for conventional operations. It would not mitigate the risk of a breakthrough in submarine detection technologies. It would likely require unilateral development – with neither major nuclear ally known to have nuclear capable SLCM programmes, indeed the US recently cancelled its nascent programme.
3. Developing a new stand-off, air-launched missile.
This is the preferred option for France as the second leg of its nuclear deterrent and is also utilised by Israel and the US as part of their deterrent mix. Air-launch promises greater flexibility of deployment and targeting than would an SLCM. The UK could diversify its risk by collaborating with France – perhaps on a nuclear capable version of the deep strike cruise missile that both are currently developing. While Tempest remains in development, the missile could be launched from a Eurofighter (France currently pairs its ASMP-A with the maritime and air force Rafale). The two countries are engaged in separate 6th generation fighter programmes, but there might be further scope for integration here too, or in other future (uncrewed) aerial platforms that might deliver a nuclear cruise missile.
Broadening the deterrent by whatever means has implications for Britain’s nuclear strategy. It is consistent with the existing notion of ‘minimal deterrent’. It’s also consistent with the refusal to make a ‘no first use’ declaration; and, if anything, it enhances the deterrent value of that position by providing more options short of general war.
Introducing new delivery systems enhances ambiguity about both what is targeted and how. For example, it raises the possibility of something like the French notion of using a nuclear weapon as a ‘final warning’ – by clearly distinguishing between that single launch and a mass retaliatory wave of SLBMs.16 It perhaps also reintroduces to British strategy the possibility of clearly distinct counterforce versus countervalue targeting.
The UK has developed a reliable, relatively low-cost ‘minimal deterrence’ centred on SSBN and SLBM technologies. Technological, geopolitical, and societal changes may weaken its future ability to do so, without the acquisition of additional weapon systems. Today, the UK has the least diverse delivery-mix of any nuclear-armed state, save North Korea. If nuclear deterrence is analogous to an insurance policy, the UK would do well to review its premiums.
This short memo represents the personal view of the author, not of any institution or organisation. It is produced at the unclassified level and draws on no classified information.
Lucy Fisher Editor Defence, ‘Repairs Left Two in Four Trident Subs out of Action’, 11 April 2023, sec. news, https://www.thetimes.co.uk/article/repairs-left-two-in-four-trident-subs-out-of-action-07jkwgtbj.
Sebastian Brixey-Williams, ‘Will the Atlantic Become Transparent?’ (British Pugwash, November 2016), https://britishpugwash.org/wp-content/uploads/2016/11/Will-the-Atlantic-become-transparent-.pdf; Owen R. Cote, ‘Invisible Nuclear-Armed Submarines, or Transparent Oceans? Are Ballistic Missile Submarines Still the Best Deterrent for the United States?’, Bulletin of the Atomic Scientists 75, no. 1 (2 January 2019): 30–35, https://doi.org/10.1080/00963402.2019.1555998.
Matthew Jones, The Official History of the UK Strategic Nuclear Deterrent. Volume I, From the V-Bomber Era to the Coming of Polaris, 1945-70, Government Official History Series (London: Routledge, 2017).
Michael Kandiah and Gillian Staerck, The British Response to SDI (Centre for Contemporary British History, University of London, 2005), https://www.kcl.ac.uk/sspp/assets/icbh-witness/sdi.pdf.
Julian Borger, ‘UK Lobbies US to Support Controversial New Nuclear Warheads’, The Guardian, 1 August 2020, sec. World news, https://www.theguardian.com/world/2020/aug/01/uk-trident-missile-warhead-w93-us-lobby.
Ewen MacAskill and Pippa Crerar, ‘Donald Trump Tells Nato Allies to Spend 4% of GDP on Defence’, The Guardian, 11 July 2018, sec. World news, https://www.theguardian.com/world/2018/jul/11/donald-trump-tells-nato-allies-to-spend-4-of-gdp-on-defence.
Julian E. Barnes and Helene Cooper, ‘Trump Discussed Pulling U.S. From NATO, Aides Say Amid New Concerns Over Russia’, The New York Times, 15 January 2019, sec. U.S., https://www.nytimes.com/2019/01/14/us/politics/nato-president-trump.html.
Aaron Blake and Michael Birnbaum, ‘Trump Says He Threatened Not to Defend NATO against Russia’, Washington Post, 22 April 2022, https://www.washingtonpost.com/world/2022/04/22/trump-says-he-threatened-not-defend-nato-russia/.
Deborah Haynes, ‘US General Warns British Army No Longer Top-Level Fighting Force, Defence Sources Reveal’, Sky News, accessed 13 April 2023, https://news.sky.com/story/us-general-warns-british-army-no-longer-top-level-fighting-force-defence-sources-reveal-12798365.
‘Russia Says Shoigu Discussed Alleged Ukraine “dirty Bomb” Threat with Indian Counterpart | Reuters’, accessed 12 April 2023, https://www.reuters.com/world/russia-says-shoigu-discussed-alleged-ukraine-dirty-bomb-threat-with-indian-2022-10-26/.
Bruno Waterfield Warsaw Brussels | Paulina Olszanka, ‘Macron Breaks Ranks by Ruling out Nuclear Option in Response to Putin’, 13 October 2022, sec. world, https://www.thetimes.co.uk/article/macron-rules-out-using-nuclear-weapons-in-response-to-putin-c7q2vwx8s.
Dawn Stover, ‘The British Government Doesn’t Want to Talk about Its Nuclear Weapons. The British Public Does’, Bulletin of the Atomic Scientists (blog), 6 April 2023, https://thebulletin.org/2023/04/the-british-government-doesnt-want-to-talk-about-its-nuclear-weapons-the-british-public-does/.
Claire Mills and Esme Kirk-Wade, ‘The Cost of the UK’s Strategic Nuclear Deterrent’, 13 April 2023, https://commonslibrary.parliament.uk/research-briefings/cbp-8166/.
Ben Clements, ‘British Public Opinion and UK-US Relations: “We like You a Lot but We Don’t Much like Your President”’, British Politics and Policy at LSE (blog), 2 June 2019, https://blogs.lse.ac.uk/politicsandpolicy/british-public-opinion-and-uk-us-relations/.
Bruno Tertrais, ‘A Comparison between US, UK and French Nuclear Policies and Doctrines’ (Sciences Po, Centre National de la Recherche Scientifique, 2007), https://www.sciencespo.fr/ceri/sites/sciencespo.fr.ceri/files/art_bt.pdf.