Select Committee on Defence Ninth Report


4  The scale of the UK's nuclear deterrent

Table 4: Reductions in the UK's nuclear deterrent to a minimum credible deterrent
For  Against 
The size of the UK's nuclear deterrent is small in comparison with that of other nuclear weapon states. The UK has only one weapons system, whereas the US, France, Russia and China each have three different systems, deployable by land, air and sea.   
 The UK's nuclear forces may be small in an international context but they still have sufficient explosive power to cause horrific destruction on an unimaginable scale. The destructive power of the UK's nuclear weapons has increased with each new generation of weapons.  
The 1998 Strategic Defence Review made substantial reductions to the size of the UK's nuclear deterrent, abandoning the air-based free-fall nuclear bombs and cutting the number of operationally available warheads from around 300 to under 200.   
 The SDR did not go far enough. It rationalised the UK's nuclear forces and abandoned obsolete weapons, rather than a comprehensive disarmament measure.  
The White Paper announces further reductions in the UK's nuclear warhead stockpile, from up to 200 warheads to up to 160 warheads. The UK's nuclear arsenal now accounts for less than 1% of the global inventory of nuclear weapons.   
 The reductions announced in the White Paper are welcome, but they will have no impact on the number of deployed warheads. Since each submarine will still sail with up to 48 nuclear warheads on board, the measures announced in the White Paper will have no practical effect.  
 The reductions announced in the White Paper are contrived. They are rationalisation measures taken for logistical reasons. They are not meaningful disarmament measures.  
The UK operates a "minimum" nuclear deterrent.   

It is not clear how the Government determines what constitutes a minimum nuclear deterrent. Unless the Government states how it calculates this, the public will be unable to judge that claim.  
Other nuclear weapon states take a different view on what constitutes a minimum deterrent. The UK consistently engages others in the international community with a view to minimising weapon numbers and seeing through its international commitments collectively.   

The Government's policy on nuclear weapons

51. The Government states that its "overarching policy on nuclear weapons remains as set out in the December 2003 Defence White Paper," Delivering Security in a Changing World.[62] This states that

We are committed to working towards a safer world in which there is no requirement for nuclear weapons and continue to play a full role in international efforts to strengthen arms control and prevent the proliferation of chemical, biological and nuclear weapons. However, the continuing risk from the proliferation of nuclear weapons, and the certainty that a number of other countries will retain substantial nuclear arsenals, mean that our minimum nuclear deterrent capability, currently represented by Trident, is likely to remain a necessary element of our security.[63]

52. The current White Paper states that "the UK will retain only the minimum amount of destructive power required to achieve its deterrent objectives".[64] The White Paper does not propose any fundamental change to the UK's nuclear weapons policy.

Reductions announced in the scale of the UK's nuclear deterrent

53. The White Paper announces changes to the scale of the UK's nuclear deterrent. In particular, it announces reductions in the number of operationally available warheads, from "the present position of fewer than 200 to fewer than 160," as well as a "corresponding 20% reduction in the size of our overall warhead stockpile".[65] The UK's current holding of Trident D5 missile has been reduced to 50.[66]

54. These measures are additional to the significant reductions in the scale of the UK's nuclear deterrent announced in the 1998 Strategic Defence Review (SDR): a one third reduction in the number of operationally available warheads, from 300 to 200, and a reduction of the number of warheads deployed on each Vanguard submarine from 96 to 48.[67] At the time, the Government stated that these changes were intended "to reduce the scale and readiness of our nuclear forces to ensure they are the minimum necessary to achieve our deterrent objectives".[68] In turn, the reductions announced in the SDR were in addition to the disarmament measures taken between 1991 and 1998, which included the withdrawal of the Lance system, the US tactical nuclear warheads mounted on heavy artillery and the RAF's sub-strategic air-launched nuclear weapons (the WE 177 free-fall nuclear bombs).

55. The Government states that the further reductions announced in the White Paper

will mean that, since coming to power in 1997, we will have reduced the upper limit on the number of operationally available UK nuclear warheads by nearly a half. Since the end of the Cold War, the UK will have reduced the overall explosive power of its nuclear arsenal by around 75%. The UK's nuclear deterrent now accounts for less than 1% of the global inventory of nuclear weapons, and our stockpile is the smallest of those owned by the five nuclear weapon states recognised under the Nuclear Non-Proliferation Treaty.[69]

56. The UK has abandoned the concept of a nuclear triad, where weapons are deployed by air, land and sea, whereas the United States, France, Russia and China all have powerful systems in all three areas, and Israel, Pakistan and India are all believed to be actively seeking to develop a full nuclear triad. The UK's nuclear arsenal is small in comparison to that of other established nuclear powers. The UK has made very significant reductions in the scale of its nuclear arsenal since the end of the Cold War.

Significance of the reductions

57. Some witnesses to our inquiry have questioned the significance of the reductions in the UK's nuclear weapons stockpile announced in the White Paper. The Scottish CND, for example, argues that "the White Paper does not propose any reduction in the number of warheads deployed at sea" with the result that "the reduction will be achieved by scrapping warheads that are currently held in reserve, but operationally available". It claims that since the "practical step towards disarmament" of the 1998 Strategic Defence Review was "the removal of 36 warheads from submarines," the White Paper enables the Government to "make one reduction but claim the credit for it twice".[70] Similarly, Paul Ingram, of BASIC, regards the warhead reductions to be "almost irrelevant because we will still have 48 warheads out on patrol at any time".[71] According to Mr Ingram, the decisions in the White Paper mean that the Government is "planning to have pretty much a status quo into the indefinite future".[72] Greenpeace, too, maintains that "the potential arsenal carried by a Vanguard submarine on patrol remains unchanged despite any wider stockpile changes proposed in the White Paper". It argues that "whilst physical numbers might have changed" since the end of the Cold War, "the actual capability of Britain's nuclear weapons stockpile has increased".[73]

58. Although broadly supportive of the White Paper, Dr Jeremy Stocker, of the International Institute for Strategic Studies (IISS), questioned the operational significance of the reduction in warhead numbers. He argues that the White Paper offered "no operational justification…for the 20% reduction in operationally available warheads". He suggests that the measure might have "more to do with diplomatic and domestic political gestures than the requirements of a "minimum" deterrent, the minimum size of which has been repeatedly reduced since the end of the Cold War".[74]

59. Other commentators suggest that logistical factors, rather than a commitment to disarmament, lie behind the reduction in warhead numbers. For example, Bruce Kent, of CND, told us that the reductions in warhead numbers, though "certainly…welcome," more likely reflect "good housekeeping," the Government reasoning that "there is no point spending fortunes on thousands of violent weapons when you can do it with 50 or five".[75] Similarly, Di McDonald, of the Nuclear Information Service, suggested that "all the reductions that there have been so far have been for logistical reasons". She argues that the reductions to date "have not been disarmament measures, they have been measures to remove old weapons that have become obsolete and they have been measures of efficiency". She maintains that "there was never any stage that we reached the original 512 capability number of warheads for Trident because it was actually impossible in the way that Aldermaston is configured".[76] Dr Rebecca Johnson, Executive Director of the Acronym Institute for Disarmament Diplomacy, meanwhile, argues that that while the 20% reduction "looks good," the new ceiling of 160 warheads "may…be little more than a political bid to make a virtue out of necessity". Dr Johnson told us that this argument is based upon calculations which have been made of "the frequency and size of the nuclear warhead convoys between Aldermaston and Coulport" which "suggest that Britain may not have manufactured more than 160-170 warheads for the current Trident system". Dr Johnson argues that, by proposing only minor reductions, the White Paper effectively "proposes business as usual".[77]

60. We asked the Secretary of State for Defence how he would respond to these criticisms. He argued that the cuts announced in the White Paper meant that "we will be dismantling around 40 warheads". In his judgement, this represented "quite a significant reduction in the number of warheads that we presently have". He maintained that "people should not minimise that, nor should they minimise the fact that we have in the time we have had stewardship…of this deterrent halved the number of warheads".[78] Mr Browne denied that any reduction had already taken place and argued that the proposed cuts were the result of a review of the UK's capability requirements. He stated that

This is the first time we have changed the size of our stockpile since the decisions we announced in the Strategic Defence Review in 1998 and it is driven by analysis, a very hard analysis, of the capability that we believe we require…this process was a difficult and challenging process and we went through it with a view to ensuring that we did have the minimum deterrent which has always been our policy.[79]

61. We asked the Secretary of State what constituted a minimum nuclear deterrent. He told us that it was "the capability that we judge is necessary to provide an effective deterrent posture". A "proper deterrent," he argued, "needs to be not just minimum but credible and operationally independent". It meant that the UK needed to be able "to influence a potential enemy anywhere in the world" and affect "the decision-making process of any potential future aggressors".[80]

62. Mr Browne maintained that it was "instructive that we have, as one of a small number of nuclear weapon states, one percent of the nuclear warhead capability in the world". He suggested that it was "clear that other countries take a different view if they are seeking to achieve a minimalist approach". And he argued that "we want…to engage others with a view to minimising" their nuclear arsenals.[81] He concluded that "we are committed to maintaining the minimum nuclear deterrent but that minimum has to offer a credible threat to any potential aggressors".[82]

63. We welcome the reduction in warhead numbers announced in the White Paper and recognise that this follows the significant reductions previously announced in the 1998 Strategic Defence Review. We welcome this arms reduction measure, but it is unclear whether this has significance as a non-proliferation measure. Since the White Paper proposes no changes to the number of warheads deployed on UK submarines, it is unclear that this reduction has any operational significance.

64. The White Paper states that the UK is committed to maintaining a "minimum" nuclear deterrent. The Secretary of State told us that the Government had conducted a very hard analysis of the nuclear capabilities required by the UK with a view to ensuring that they were at a minimum necessary level, but we are uncertain how the Government determines what constitutes a "minimum" deterrent. The Government should say how it calculates the scale of a minimum deterrent.

62   Cm 6041 Back

63   Cm 6041, para 3.11 Back

64   Cm 6994, para 3.4, p 17 Back

65   Cm 6994, para 2.3, p 12 Back

66   Cm 6994, para 2.5 Back

67   Cm 3999, p 18 Back

68   Cm 6994, para 2.3 Back

69   Cm 6994, para 2.4 Back

70   Ev 87 Back

71   Q 196 Back

72   Ibid. Back

73   Ev 184 Back

74   Ev 110 Back

75   Q 75 Back

76   Q 76 Back

77   Ev 198 Back

78   Q 348 Back

79   Q 350 Back

80   Q 346 Back

81   Q 347 Back

82   Ibid. Back


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