Select Committee on Defence Ninth Report


6  International legal and treaty aspects

Table 6: The Government's proposals are consistent with international law and the UK's treaty obligations: arguments for and against
For  Against 
Retaining the nuclear deterrent is fully consistent with the UK's international legal obligations. The Non-Proliferation Treaty recognises the UK's status as a nuclear weapons state and does not call for immediate and unilateral disarmament.   
 Retaining a nuclear deterrent is in breach of Article VI of the Non-Proliferation Treaty which obliges the UK, and the other nuclear weapon states, to negotiate in good faith towards disarmament.  
Article VI has to be read as a whole—the requirement is to pursue negotiations in good faith, towards general and complete disarmament as well as nuclear disarmament. The UK has made significant steps towards nuclear disarmament (number of nuclear warheads reduced from 300 to 200 since 1998, number of Trident D5 missiles reduced to 50) and now plans to reduce its stockpile of nuclear warheads to fewer than 160.   
 But there is no plan to reduce the number of warheads on each submarine, so this has no operational significance.  
The UK has also made significant diplomatic efforts to encourage non-proliferation, which are outlined in detail in an annex to the White Paper.   
 Renewal of the nuclear deterrent will make it harder to persuade other States that it would be wrong to acquire nuclear weapons - and might even encourage nuclear proliferation.  
Simply acquiring a new platform (the submarine) is certainly not against the NPT.   
 Acquiring a new submarine may not be illegal, but the decision to extend the life of the Trident missiles is more doubtful.  
 Extending deterrence theory to state-sponsored terrorism is dangerous. It might breach the NPT and lower the nuclear threshold  
The decision on the future of the deterrent is essentially a political and not a legal one.   

101. In this part of the report, we consider the challenges made to the legality of the Government's proposals to retain and renew the UK's nuclear deterrent and the arguments that the proposals are damaging to international efforts to stem nuclear proliferation.

The legality of the White Paper's proposals

The Government's position

102. In the White Paper, the Government states that the "the UK's retention of a nuclear deterrent is fully consistent with our international legal obligations". It states that the Nuclear Non-Proliferation Treaty (NPT) "recognises the UK's status (along with that of the US, France, Russia and China) as a nuclear weapons State". It states that the NPT "remains the principal source of international legal obligation relating to the possession of nuclear weapons". It concludes that "we are fully compliant with all our NPT obligations, including those under Article I (prevention of further proliferation of nuclear weapon technology) and Article VI (disarmament).[135]

103. The White Paper states that the NPT does not insist upon immediate and unilateral disarmament by the UK and "does not establish any timetable for nuclear disarmament, nor for the general and complete disarmament which provides the context for total nuclear disarmament. Nor does it prohibit maintenance or updating of existing capabilities". It states that the Government "will continue to press for multilateral negotiations towards mutual, balanced and verifiable reductions in nuclear weapons".[136]

104. The White Paper also says that, in 1996, "the International Court of Justice delivered an Advisory Opinion which confirmed that the use, or threat of use, of nuclear weapons is subject to the laws of armed conflict" and maintains that the Court "rejected the argument that such use would be unlawful". The White Paper provides an assurance that "we would only consider using nuclear weapons in self-defence (including the defence of our NATO allies), and even then only in extreme circumstances". But it notes that "the legality of any such use would depend upon the circumstances and the application of the general rules of international law, including those regulating the use of force and the conduct of hostilities".[137]


105. Some witnesses to our inquiry have challenged the legality of the proposals contained in the White Paper. The CND, for example, argues that the Government "misrepresents both Britain's obligations under the nuclear Non-Proliferation Treaty and, and the position of the International Court of Justice on the use, or threat of use, of nuclear weapons". CND suggests the White Paper's description of the UK as a "recognised" nuclear weapon state is not only "misleading," but is "part of an ongoing attempt to reinterpret the NPT to suggest that nuclear weapons states are somehow legally entitled by that Treaty to possess nuclear weapons". CND maintains that the NPT provided no such legal entitlement to nuclear weapons; its reference to "recognised" nuclear weapons states, was merely a statement of fact about which countries possessed nuclear weapons at the time of the negotiation of the Treaty.[138] According to CND, the International Court of Justice (ICJ) did not reject the argument that the threat or use of nuclear weapons would be unlawful, as the White Paper suggests. It cites the verdict of the Court, which stated that "the threat or use of nuclear weapons would be generally contrary to the rules of international law applicable in armed conflict and in particular the principles and rules of humanitarian law".[139] CND also maintains that the ICJ "gave "no opinion" on whether the use of nuclear weapons might be legal in a situation of extreme self defence where the existence of the state was threatened".[140] This argument is also made by Abolition 2000, which suggests that the ICJ "indicated that immediate [disarmament] negotiations were…called for" but that "the UK is not currently involved in any such negotiations".[141]

106. Dr Rebecca Johnson, like CND and Abolition 2000, argues that "the replacement of Trident would constitute a breach of Article VI of the NPT". And she maintains that this would constitute a "material breach" of the Treaty as a whole. Dr Johnson suggests that while reductions in the scale of the UK's nuclear deterrent since the end of the Cold War are welcome, "the Article VI obligation is not just to reduce the nuclear arsenals, but to eliminate them". The decisions contained in the White Paper, she argues, constitute "an overall increase in capability and longevity" of the UK's nuclear deterrent" and that this is inconsistent with the legal obligations imposed by the NPT. Dr Johnson also contends that the Government cannot base its decisions on the failure of other countries to honour the Treaty; "other governments' failures to take their treaty obligations seriously cannot constitute a justification for the present government to make the same mistakes".[142]

107. Professor William Walker states that the White Paper's claim that the UK's retention of a nuclear deterrent is fully consistent with its international legal obligations is "contestable". He argues that "the right to hold nuclear weapons," implied in the NPT, "is neither permanent nor unconditional". He states that "replacing Trident is not easily reconciled with that obligation".[143]

108. The British Pugwash Group makes a similar argument. It maintains that the NPT "gives us specific responsibilities under Article VI to negotiate in good faith towards a nuclear weapon free world" and that "renewing Trident, even with the fudge of a possible reduction in warhead numbers, is hardly consistent with this responsibility".[144]

109. As part of our inquiry, we took oral evidence from four of the UK's leading international legal experts: Professor Christopher Greenwood QC of the London School of Economics, Professor Nick Grief of the University of Bournemouth, Professor Steven Haines of Royal Holloway College, University of London, and Professor Philippe Sands QC of University College London. We asked them for their opinion on what role legal issues should play in decisions over the future of the UK's nuclear deterrent, whether the decisions contained in the White Paper were legal or illegal and how the UK's obligations under the Non-Proliferation Treaty were relevant to the discussions on the future of the deterrent.

110. In evidence to our inquiry, Professor Grief told us that "even to maintain the deterrent raises issues under Article VI of the Non-Proliferation Treaty". The Treaty, he maintained, places obligations upon the UK "to negotiate in good faith towards nuclear disarmament". Professor Grief told us that "I do not see sufficient evidence in the White Paper of movement on the part of the Government in the direction of nuclear disarmament and, therefore, in the direction of fulfilling the obligations of Article VI".[145] The requirement to negotiate "in good faith," argued Professor Grief, meant "not negotiating from an entrenched position, negotiating sincerely towards the objective that in enshrined in the Treaty, namely nuclear disarmament, and doing nothing which would be likely to render fulfilment of that obligation remote or impossible".[146] Professor Grief also maintained that the use and threat of use of nuclear weapons by the UK was illegal under international humanitarian law.

111. Professor Sands told us that he was concerned at "the apparent extension of deterrence theory into areas related to terrorism," which, he argued, "does raise…issues in relation to the Treaty on Non-Proliferation of Nuclear Weapons".[147] By extending the theory of deterrence in this way, Professor Sands maintained, "you open a door to the argument of illegality" and "you send out a signal to others who may also want to adopt a different approach to their obligations under the [Non-Proliferation] Treaty".[148] According to Professor Sands, if the international community is to enforce the NPT effectively, and to challenge credibly those who contravene it, "we need to be absolutely certain that we are fully meeting our own obligations".[149]

112. Both Professor Haines and Professor Greenwood, however, argued that the Government's plans to retain and renew the UK's nuclear deterrent were legal. Professor Haines told us that "I do not believe there is any problem with the proposal in the White Paper of a legal nature…the proposal is both appropriate and expected given the history of Trident".[150] And he stated that "the issue of whether we should go down the route that the Government is suggesting is entirely a policy decision". He argued that "there is nothing in the NPT that says we have to give [nuclear weapons] up in a unilateral sense".[151] He argues that

Possession of nuclear weapons is not contrary to international law, although nuclear weapon states are under an obligation to move towards disarmament…the British strategic nuclear deterrent capability is lawful; it is fully in accordance with international law and does not represent a breach of that law in any way. There has never been a persuasive argument deployed to establish illegality.[152]

113. Professor Greenwood agreed. He maintained that "legal aspects should not be decisive" and that the decisions facing the country were of a political rather than a legal nature.[153] In his judgement, "in terms of international law there is no obstacle whatever to the Government doing what it has proposed to do". He told us, "I do not believe that either the Non-Proliferation Treaty or the laws of armed conflict would preclude updating Trident in the way that is suggested".[154] Like Professor Haines, Professor Greenwood maintained that the NPT imposed no obligation upon the UK to disarm unilaterally.[155]

114. The Government states that the retention and renewal of the UK's nuclear deterrent is fully consistent with its international legal obligations. Some witnesses to our inquiry challenged the Government's position and suggested that the proposals in the White Paper may constitute a breach of the Nuclear Non-Proliferation Treaty and may be illegal under the UN Charter and international humanitarian law. The Government rejects this suggestion. None of the witnesses to our inquiry, however, believed that a decision to replace the Vanguard-class submarines would, in itself, be illegal, though some argued that the long-term retention of a nuclear capability, including the decision to extend the life of the Trident D5 missile, was inconsistent with the UK's obligations to pursue negotiations in good faith to achieve nuclear disarmament.

115. Witnesses to our inquiry accepted that, ultimately, decisions on the future of the future of the UK's nuclear deterrent were political and that, in the absence of consensus, legal concerns were unlikely to be decisive.

The NPT and nuclear proliferation

116. Some of the witnesses to our inquiry argued against the Government's proposal to retain and renew the nuclear deterrent on the grounds that it would be damaging to international negotiations to prevent the proliferation of nuclear weapons and to the UK's credibility in those negotiations.

117. In the White Paper, the Government reiterates the pledge made in the 2003 Defence White Paper 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 spread proliferation of chemical, biological and nuclear weapons.

The current White Paper recounts the UK's efforts to promote nuclear disarmament and non-proliferation through the NPT, the Conference on Disarmament and the UN Disarmament Commission. And it states that "we stand by our unequivocal undertaking to accomplish the total elimination of nuclear weapons".[156] Reference is made to the Norwegian 7 Country Initiative, which aims to foster fresh thinking on how we can take forward the three pillars of the NPT—access to nuclear technology for exclusively peaceful purposes, non-proliferation and disarmament.[157]

118. In evidence to us, the Secretary of State for Defence maintained that the UK had "a good record in living up to our international obligations in this regard". He told us that

we continue to support and we have made progress in 13 practical steps towards the implementation of Article VI agreed in 2000; we have ratified the Comprehensive Nuclear Test Ban Treaty; we have increased our transparency by publishing historical accounting records of our defence fissile material holdings; we have pursued a widely welcomed programme to develop expertise in methods and technologies that could be used to verify nuclear disarmament on which we have produced a series of working papers, culminating in a presentation to the 2005 NPT Review Conference.[158]

119. Mr Browne also stated that

our priority remains to press for negotiations in the Conference on Disarmament of the Fissile Material Cut-Off Treaty; we welcome the draft text which the United States tabled last year; we hope that all concerned are able to accept the very broad mandate proposed and agree to open negotiations towards a treaty without delay, and we are also actively engaged in the global initiative to combat nuclear terrorism, where we will be playing a key and active role in shaping and contributing to the forward-looking programme of this important new development.[159]

120. We asked what impact the White Paper would have on the UK's non-proliferation efforts. Ms Mariot Leslie, Director, Strategic Threats at the Foreign and Commonwealth Office, told us that "we found a gratifying degree of understanding for the Government's decision on the part in particular of our NATO allies but also a large number of other countries". According to Ms Leslie, at the Conference on Disarmament "a number of countries went out of their way to congratulate the Government on the degree of transparency it had gone in for in the White Paper," which, she said, was one of the 13 practical steps agreed to by the 2000 NPT Review Conference.[160]

121. Some witnesses to our inquiry, however, suggested that the Government's justification of the retention and renewal of the UK's nuclear deterrent as an insurance against an uncertain future was an argument that could be used by other states in defending their attempts to acquire nuclear weapons. CND, for example, argues that "Trident replacement…will encourage nuclear proliferation". It states that "it is vital that sincere initiatives are taken, by the nuclear weapons states, towards disarmament, otherwise non-nuclear weapons states may conclude that there is no reason for them to stick to their side of the NPT bargain".[161] Similarly, Scottish CND maintains that "every nation in the world could use the arguments suggested [in the White Paper] to show why they needed the bomb," and that "if each country only considers itself then nuclear proliferation will accelerate". It argues that "we should be working with others to prevent… this apocalyptic future".[162]

122. A similar argument is put forward by Dr Stephen Pullinger, who maintains that

Essentially there is a tension in policy between extolling the value of nuclear weapons for Britain's security while seeking to deny such capability to others. The danger is that by affording nuclear forces a high importance within national defence and security strategies we undermine our efforts to persuade other states that they can do without such forces themselves.[163]

According to Dr Pullinger, this "double standard argument…goes to the heart of the link between nuclear weapon possession and non-proliferation". In his opinion, it "prompts the fundamental question as to whether it is possible to tackle proliferation effectively, while still insisting that nuclear weapons are necessary for Britain's security, but not for others". He concludes that "the entire non-proliferation regime is creaking under the strain" of this double standard and argues that "unless we address its underlying problems it may disintegrate with dire consequences for all of us".[164]

123. David Broucher, a former head of the UK delegation to the UN Disarmament Conference and now a Research Fellow at the University of Southampton, maintains that, in absolute terms, the UK's decision on whether to retain and renew its nuclear deterrent will not encourage proliferation, but that its propaganda effect may undermine the international consensus needed to prevent the spread of nuclear weapons. He argues that

It seems most unlikely that would-be proliferators would be influenced definitively either way by the UK's decision. Strategic weapon policies emerge over decades for a wide variety of reasons and are not susceptible to short-term change based on the calculation of one other country…On the other hand, the UK's decision will undoubtedly be used as a political defence by would be proliferators, and the resulting propaganda will have some influence with uncommitted countries whose support we need to retain if we are to uphold the efficacy of non-proliferation regimes.[165]

In the longer term the danger is that the UK's decision will be taken as one of a number of factors indicating that nuclear weapons are now a permanent feature of the international security environment…which could combine with other factors that are already eroding confidence in the Non-proliferation Treaty and contribute to a seismic shift in international security postures.[166]

124. According to Mr Broucher, progress towards bilateral and multilateral disarmament has "stalled, and even gone into reverse". He argues that "the UK has ceased, for whatever reason, to advocate multilateral nuclear disarmament with any conviction" and he suggests that, in the absence of any enthusiasm amongst the other nuclear weapon states, the disarmament process "risks stagnating," a trend which he fears "will not easily be reversed".[167] As a possible remedy, Mr Broucher argues that future international agreements should, if necessary, rely on remote verification to ensure compliance, such as that pioneered by the UK Atomic Weapons Establishment, rather than insist upon on-site inspections, which have hitherto impeded negotiations. He also suggests that further consideration should be given to the idea of "security assurances" as a means of discouraging further nuclear proliferation.[168]

125. In a similar vein, Professor Michael MccGwire argues that in any discussion over the future of the UK's nuclear deterrent, consideration should be given to the "opportunity costs" of retention and renewal—"things Britain could do and achieve (if it were not a nuclear weapon state)". He maintains that, at present, the Non-Proliferation Treaty is "increasingly in jeopardy". The nuclear weapon states, he suggests, "are not observing their side of the bargain," and stand accused of employing "double standards," maintaining their own nuclear arsenals whilst denying nuclear weapons to others. According to Professor MccGwire, "the NPT is increasingly seen as part of a larger Western conspiracy" and is "failing the crucial test of being seen as "fair"".[169]

126. The White Paper states that the Government is committed to nuclear non-proliferation and to the ultimate goal of nuclear disarmament. It cites a variety of ways in which the Government has sought to achieve these objectives. Some witnesses to our inquiry, however, have argued that the White Paper gives insufficient attention to the implications of the Government's decisions for non-proliferation efforts. Some argued that the Government's proposals may actually encourage nuclear proliferation and undermine the authority of the Non-Proliferation Treaty. Others have argued that whether the UK opts for or against retaining its nuclear deterrent, the decision will have a negligible impact on global proliferation.

127. The reductions in warhead numbers announced by the White Paper are significant disarmament measures, but, in themselves, they do not amount to a non-proliferation strategy. There is a need for a much stronger narrative on the forward commitment of the Government to achieve nuclear non-proliferation. The Government should not assume that current activities such as those mentioned in respect of the Norwegian 7 Country Initiative have a wide currency. The Government should explain how it will use its position at the Security Council, as the only nuclear weapon state with a single platform and 1% of the global arsenal, to give new momentum to what are widely perceived as stalled non-proliferation treaty discussions. Without a stronger narrative, the UK's decision to retain and renew its nuclear deterrent might be seized upon by would-be proliferators to justify their own efforts to acquire nuclear weapons, though it remains the case that any non-nuclear state which is a signatory to the NPT is in clear breach of its undertakings if it seeks to acquire nuclear weapons.

135   Cm 6994, para 2.9, p 14 Back

136   Cm 6994, para 2.10, p 14 Back

137   Cm 6994, para 2.11, p 14 Back

138   Ev 81 Back

139   Ev 82 Back

140   Ibid. Back

141   Ev 131 Back

142   Ev 196 Back

143   Ev 166 Back

144   Ev 129 Back

145   Qq 219, 221 Back

146   Q 236 Back

147   Q 209 Back

148   Q 210 Back

149   Q 216 Back

150   Q 209 Back

151   Q 233 Back

152   Steven Haines, "Is Britain's continued possession and threatened use of nuclear weapons illegal?", The Future of Britain's Nuclear Weapons: Experts reframe the debate, Oxford Research Group, March 2006, p 56 Back

153   Q 210 Back

154   Q 209 Back

155   Q 237 Back

156   Cm 6994, p 13 (Box 2.1) Back

157   Cm 6994, p 33 Back

158   Q386 Back

159   Ibid. Back

160   Q 392 Back

161   Ev 81 Back

162   Ev 88 Back

163   Ev 107 Back

164   Ev 108 Back

165   Ev 139 Back

166   Ev 140 Back

167   Ibid. Back

168   Ibid. Back

169   Ev 200 Back


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