Deterrence in the twenty-first century - Defence Committee Contents

3  Nuclear deterrence

What threats does the nuclear deterrent deter?

47.  The 2006 White Paper on the Future of the UK's nuclear deterrent set out four deterrent roles for UK nuclear weapons:

To deter against the re-emergence of a major direct nuclear threat to the UK or our NATO allies, and to prevent major war which threatens the British state;

To deter against the use of weapons of mass destruction by a rogue state during a regional intervention in which UK forces were involved, allowing the UK to continue to be able to intervene militarily around the world without fear of "nuclear blackmail" or coercion;

To deter against state-sponsored acts of nuclear terrorism; and

To act as an insurance against emerging threats to the UK's vital interests and the uncertainties and risks of the future.[37]

48.  In respect of the first deterrent role, the Nuclear Information Service told us that Russia or China were the only nations that could pose such a threat to the UK in the foreseeable future, but concluded that "the possibility that Russia or China would at some time over the next fifty years pose a direct military threat to the UK represents an unlikely and exceptionally worst case scenario [...] It is time for the government to accept that Russia and China do not pose a military threat to the UK and that they are now becoming our economic and strategic partners".[38] Dr Nick Ritchie, University of York, acknowledged continuing tensions between both countries and the West, and acknowledged that some political crises might have military dimensions, but concluded that it was "barely conceivable that UK nuclear deterrent threats and consideration of using nuclear weapons against Russia or China will ever be part of the solution to future confrontations".[39]

49.  However, Franklin C Miller, a former Special Assistant at the White House and Senior Director for Defense Policy and Arms Control at the National Security Council, has argued, in contrast, that calls from the UK and the US for the worldwide elimination of nuclear weapons "has not drawn obvious support from France, Russia, China, India, Pakistan, Israel, North Korea or Iran" and that the current Russian leadership placed a "very high reliance on nuclear weapons", and had threatened nuclear use against its neighbours, including running an exercise which simulated nuclear weapons attacks on Poland. [40] He added that Russian nuclear forces were put on a state of alert during the Russian invasion of Georgia in 2008 to guard against "NATO adventurism". Mr Miller concluded that "Russia's nuclear weapons are coercive weapons and the Russian Government has been using them for such effect". He accordingly argued strongly for the retention of the UK nuclear deterrent. We note that the recent Russian intervention in Crimea was accompanied by a test of a Russian inter-continental ballistic missile, again suggesting that Russia was prepared to use its nuclear capabilities as a form of leverage in global relations.

50.  The second deterrent role envisages deterring a rogue state from using weapons of mass destruction to allow for a regional intervention. The Nuclear Information Service argued that,

If the survival of a rogue regime armed with weapons of mass destruction was genuinely under threat, military intervention would be an unpredictable high-risk option, with a disproportionate risk that the regime might use its weapons in a last-ditch attempt to survive. [41]

Ritchie noted that the dangerous "asymmetry" of the stakes where the survival of a nuclear-armed rogue state was threatened would make it unlikely that UK nuclear deterrent threats would prevent the use of nuclear weapons by that state.[42]

51.  The third of the threats that the White Paper said the nuclear capability was designed to deter was state sponsored acts of terrorism. We noted in Chapter 2 the challenges to deterrence of attack by a state that was confident in concealing its traces, either acting through a proxy or by other means. UNA-UK told us that the nuclear deterrent provided no benefit in managing the asymmetric threats posed by terrorist groups or by unstable states within which or near to which the UK had resource interests.

These frail states cannot be solidified by the UK's nuclear deterrent, and the deterrent cannot be used as leverage or as "a big stick" towards irregular forces within such states [...]. Al-Shabab does not feel threatened by any state's nuclear weapons, and the only time Al-Qaeda cogitates over any state's nuclear deterrent, is possibly to consider how it might compromise the security of it.[43]

52.  Our predecessor Committee noted in its report on The Future of the UK's Strategic Nuclear Deterrent: the Strategic Context that

The most pressing threat currently facing the UK is that of international terrorism. Witnesses to our inquiry overwhelmingly argued that the strategic nuclear deterrent could serve no useful or practical purpose in countering this kind of threat.[44]

Professor Hennessy argued that the nuclear deterrent was never designed to be a deterrent against terrorism.[45]

53.  A number of submissions to this inquiry argued that nuclear deterrence was only of relevance when dealing with rational actors. Ward Wilson, Senior Fellow at the British American Security Information Council, argued that "deterrence fails against madmen" and that "it only works with those who stop and consider rationally the costs of what they're about to do".[46] However, in responding to the charge that nuclear weapons are of no use against "non-deterrable" terrorist threats, Dr Stocker told us that there are few genuinely irrational actors.[47] He believed instead that "It is rather that not all rationalities are the same. It all depends on an individual's, a group's or a state's underlying assumptions, perceptions, beliefs and values". As noted in paragraph 16 above, Dr Stocker also argues that few threats are genuinely non-state or non-territorial in origin.

54.  General (retd) Sir Hugh Beach argued that nuclear weapons had provided no discernible benefit to the UK and certainly provided no protection against terrorism.[48] Professor Malcolm Chalmers noted that none of the scenarios that might necessitate independent use of nuclear capabilities were currently plausible and that the UK was "safer than it has ever been from the threat of conventional military attack on its homeland by another state".[49] However, he cautioned that it was "not possible to predict the shape of the international strategic environment in the 2030s or 2040s. And the continuing proliferation of nuclear weapons and related technologies increases the risk that, at some point, a direct threat to the UK might emerge".

55.  The fourth purpose of the nuclear deterrent, to act as potential retaliation against emerging threats, has been characterised as the "nuclear hedge". Professor Chalmers described the argument of the nuclear "hedge" as "while there may be no credible threat today that justifies a national nuclear deterrent, the country should hedge against the possibility that such a threat may re-emerge in future".[50]

56.  Dr Ritchie argued that nuclear weapons provided no answer to the types of threats to UK interests that were likely to arise from future uncertainty. He said that

Such threats are likely to be messy and arise from an interdependent mix of environmental, economic, military and political sources of insecurity. These include the effects of climate change, mass poverty and global economic injustice, global pandemic diseases, mass migration, and refugee flows, weak and failing states, international terrorism and asymmetric warfare, the spread of WMD and advanced conventional military technologies, ethnic and sectarian nationalism and competition over access to key resources such as oil and water.[51]

He added that the "apparent certainties" of nuclear deterrence provided a "false comfort" in looking at the diversity of future threats.

57.  We note, however, that while the potential range of emergent threats is significant, they do not preclude either the re-emergence of tensions with an existing nuclear power, nor the emergence of a new power whose interests are inimical to those of the United Kingdom with the capacity to deliver a CBRN attack on the UK or its interests.

58.  The fourth of the deterrent roles identified in the White Paper is to provide potential retaliation against threats that may emerge over the next 50 years. Nuclear proliferation is not under control and many of the sources of future insecurity could in themselves contribute to state-on-state conflict , creating an ever more unstable, and increasingly nuclear-armed, future strategic context. The assessment of future threats is as important as the assessment of current threats in considering the case for the nuclear deterrent.

The opportunity cost of the nuclear deterrent

59.  Dr Ritchie drew attention to the "opportunity costs" of proceeding with Trident replacement, questioning "whether procuring another generation of strategic nuclear weaponry is an appropriate investment given the types of security threats the UK is likely to face over the coming decade".[52] CND concluded that money spent on nuclear deterrence was not spent on combating other threats and a decision not to renew the weapons system could therefore be spent improving other means of deterring threats more effectively.[53]

60.  One point to note in evaluating the opportunity cost argument is that the current SSN fleet of nuclear powered submarines, a key element in the Navy's conventional deterrence capability, relies heavily on the research and development investment in the nuclear-armed SSBN fleet and on the benefits of technological exchange.[54] A decision to dispense with the continuous at sea nuclear deterrent (CASD) would be likely to sharply increase costs in the conventional SSN fleet and may call into question the UK's ability to support and run a viable SNN programme.

61.  Dr Rebecca Johnson, Director of the Acronym Institute for Disarmament Diplomacy argued that reliance on nuclear weapons for deterrence had "skewed thinking" about deterrence and "will inevitably direct military, political, economic etc. resources towards doctrines, strategies and weapons that may not be appropriate or effective for the desired purposes, or even be counterproductive for security".[55] The Nuclear Information Service called on the UK to focus more on tackling risks at source and taking steps to improve resilience and self-sufficiency. [56]

62.  The MoD stated that

Effective deterrence is predicated upon being able to put oneself in the shoes of those whom one is seeking to deter. This is likely to require significant up-front investment in intelligence, engagement (where possible) and in cultural awareness.[57]

63.  The operation of a nuclear deterrent clearly does not obviate the need for substantial investment in other approaches to security, including the diplomatic, and measures to tackle risks at source. As we have noted, the nuclear deterrent cannot be used to deter all threats to national security. Given the importance of communication to the concept of deterrence, investment in diplomatic and intelligence assets must be integral to the UK's security apparatus. However, it would be naive of us to assume that a decision not to invest in the nuclear deterrent would release substantial funds for investment in other forms of security. We believe that the decision on the retention of the nuclear deterrent, and whether its retention is still merited as a means of deterring existential threats to the UK, should be made on its own merits, rather than on the basis of what else could be bought with the money saved.

Is there a need for the UK to retain an independent capability within NATO?

64.  General Beach also argued that Trident was not a genuinely independent capability as it was still reliant on the US for operation and maintenance and it would be inconceivable that it might be used in the face of US opposition.[58] In response to the previous Committee's report on the Future of the UK's Strategic Nuclear Deterrent: the Strategic Context, the MoD stated that

The UK Trident system is fully operationally independent of the US or any other state. Decision-making and use of the system remains entirely sovereign to the UK. Only the Prime Minister can authorise the use of the UK's nuclear deterrent, even if the missiles are to be fired as part of a NATO response.[...] All the command and control procedures are totally independent.[59]

65.  Professor Hennessy told us that, once a decision had been taken to get rid of the UK's nuclear capability, it would be practically impossible to reacquire it (in terms of the effort to reacquire the technology and skills lost and the money required).[60] Robert Gates, former US Defense Secretary, recently warned the UK against nuclear disarmament. [61]

66.  Franklin D Miller said that, during the Cold War, the UK and US Governments "believed that "two centres of [nuclear] decision" complicated Soviet decision making thus enhancing deterrence". He added that

Russian nuclear policy and acts of nuclear saber-rattling and intimidation make fairly self-evident that the need for "the second centre of decision" is still with us and will be for a long time. Although the US government remains bound to the defense of the United Kingdom by treaties and by history, we cannot be 100% confident that an aggressive Russian leadership will recognise that the US would provide a nuclear umbrella over the UK in a future crisis if the UK did not possess nuclear weapons. .[...] Faced with a credible independent British deterrent, however, we can be confident that that same Russian government would understand that there could be no possible scenario in which an attack on the United Kingdom would not draw a retaliatory blow - and thus it would be deterred from such an attack in the first place.[62]

67.  General Beach also questioned why the UK needed its own nuclear capability if the US nuclear guarantee was watertight.[63] Professor Chalmers notes that the Government argues that

The existence of an "independent centre" of decision-making can enhance the credibility of NATO nuclear deterrence in circumstances where an opponent may doubt the willingness of the US to use its own nuclear weapons.[64]

Implications of advanced conventional weapons for nuclear deterrence

68.  Dr Andrew Futter and Dr Benjamin Zala, University of Leicester, noted that the US was shifting to more advanced conventional weapons, including both an advanced offensive capability (Prompt Global Strike (PGS)) and defensive capability (Ballistic Missile Defence (BMD)); and argued that the US administration's intention was to create the conditions in which its nuclear arsenal could be reduced, signalling an intention to eventually disarm its nuclear capability.[65]

69.  These developments have substantial implications for the concept of deterrence and the ability of a state to exert some control over the escalation of a conflict. In the event of conflict between two or more nuclear-armed states, the ability to control the escalation of conflict relies on the ability to deploy a range of capabilities to escalate threats up to the point where the continued existence of the state is in question and a nuclear exchange becomes credible enough for nuclear deterrence to work. The proposed US PGS capability would provide a threat that was both extremely prompt, which would usefully increase the risk in an adversary's calculations, and a conventional capability that could be credibly used at a lower threshold of provocation. It could also be argued that it would be easier to mobilise public support for such a response, as it would not require commitment of forces on the ground and would not have the same indiscriminate destructive impact as a nuclear weapon, further enhancing its credibility.

70.  However, it could also be argued that such a threat could lower the nuclear threshold, as some proposed means of delivery may be indistinguishable from the delivery of a nuclear capability. In December 2013, the Russian Deputy Prime Minister warned the US that it would be prepared to respond to a conventional attack by PGS using nuclear weapons.[66]

71.  It is possible to foresee an environment in which the core role of nuclear deterrence - to protect a state from attack - is achieved by the deployment of advanced conventional weapons, providing both offensive and defensive capability. However, we are not yet in a position to evaluate any viable technical options. This will be a matter which our successor Committee may wish to examine further.

72.  It is not the purpose of this report to re-open the question of the future of the UK's nuclear deterrent. We did not re-examine the evidence in the detail that our predecessor Committee did. The 2015 National Security Strategy will identify a new order of threats and we will look to the 2015 Defence and Security Review to identify which of these threats the nuclear deterrent will be expected to deter.

37   The Future of the United Kingdom's Nuclear Deterrent, Cm6994, December 2006. Back

38   Ev w28 Back

39   Ev w34 Back

40   Franklin C Miller speech to Chatham House on the Future of the UK's nuclear deterrent: a view from the US, 27 May 2010. Back

41   Ev w29 Back

42   Ev w34. Back

43   Ev w17 Back

44   Eighth Report of the Committee, Session 2005-06, paragraph 88. Back

45   Ev w5 Back

46   Ev w41 Back

47   Ev w13 Back

48   Ev w6 Back

49   Small Nuclear Forces, Five Perspectives, RUSI Whitehall Report 3-11, page 19. Back

50   Small Nuclear Forces, Five Perspectives, RUSI Whitehall Report 3-11, page 20. Back

51   Ev w36 Back

52   Ev w38 Back

53   Ev w15 Back

54   The acronym SSN stands for Ship Submersible Nuclear, and denotes a nuclear-powered, general purpose, conventionally armed attack submarine. The acronym SSBN stands for Ship Submersible Ballistic Nuclear and denotes a nuclear-powered, nuclear-armed submarine. Back

55   Ev w20 Back

56   Ev w30 Back

57   Ev w2 Back

58   Ev w8 Back

59   Ninth Special Report of the Committee, Session 2005-06, Appendix, paragraph 12. Back

60   Ev w5 Back

61 Back

62   The Future of the UK's nuclear deterrent - a view from the US, speech to Chatham House, 27 May 2010, Back

63   Ev w7 Back

64   Small Nuclear Forces, Five Perspectives, RUSI Whitehall Report 3-11, page 18. Back

65   Ev w24 Back

66  "Russia warns of nuclear response to US Global Strike Programme", Moscow Times, 11 December 2013,


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