Select Committee on Defence Eighth Report

6  The substance and timing of UK decisions

The nature of the decisions facing the UK

104. The Government has stated that decisions on the future of the UK's strategic nuclear deterrent will be required during the course of the current Parliament. To date, it has offered no explanation of the nature of those decisions. If there is to be a meaningful debate on the future of the UK's strategic nuclear deterrent, the public should know what decisions will be required, when they must be taken and implemented, and what factors are driving consideration of the issue now.

105. In the broadest terms, we heard that there are four key types of decisions facing the UK in considering the future of its strategic nuclear deterrent:


106. A fundamental political decision needs to be made on whether or not the UK should retain a strategic nuclear deterrent. There is no clear point at which this decision has to be made and there is a risk that - by taking a series of decisions to keep options open - we could find that we have in practice taken the decision to keep the deterrent. Conversely, if we do not keep those options open, we could find we are left without a deterrent. In our view, the UK should make a clear decision on whether to retain the strategic nuclear deterrent. It is important that a decision of this magnitude is not taken by default. It should be made only after a full public debate. It must not be made by the Government in secret.

107. A decision on the future of the strategic nuclear deterrent is not required imminently and there is an argument for leaving it as long as possible so that the latest strategic threat can be assessed. On the other hand, we should not embark on very substantial investment in a Trident replacement system without having come to a clear decision that we want to replace it. In practice, this means that the fundamental decision will need to be made at least before a Main Gate decision on procuring a replacement to the Trident submarine.[93]


108. A broad capability decision will be required on what form any successor nuclear deterrent system should take, if retention of a strategic nuclear deterrent capability is considered necessary for national security. One option for the UK is to embark on a programme of extending the service life of the current Vanguard class SSBN submarines. The United States is currently engaged in such a programme for its Ohio-class Trident submarines.

109. Commodore Hare told us that service life extension is only a short term solution for the UK's future capability. The hulls of the UK boats, he argued, could only be extended for approximately five years. After that, the safety of the boats would become an issue and the cost of addressing such safety concerns would likely be too high to warrant a more extensive programme of upgrades.[94]

110. A service life extension programme would allow the UK to postpone decisions on whether to replace Trident until around 2010, on the basis that a service life extension programme would add an additional five years to the existing system and that procurement of a Trident replacement would take approximately 14 years. By this time, it is possible that the strategic environment might be clearer. But it is likely to be an expensive process. Such an expensive option should not be used only as a means of deferring a decision on the future of the UK's strategic nuclear deterrent.


111. In the longer-term, the UK will have to decide whether to continue with a submarine-based system, or opt for a ship-based system, an air-based system, or a land-based system as the foundation of its strategic nuclear deterrent capability or a combination of the three.

112. We heard that a final decision on future capability would be required only at the Main Gate stage of investment, though we also heard that many options would be dispensed with at the Initial Gate stage.


113. A series of decisions are required on how best to preserve the submarine construction skills base, and the nuclear warhead skills base, until conclusive decisions on both future capability and retention versus abolition are required. Some of these decisions are already being taken. The MoD's new investment programme at Aldermaston, announced in July 2005, is expressly intended to maintain infrastructure and preserve the UK skills base.

114. In December 2005, the MoD published the Defence Industrial Strategy, which emphasised the importance of driving down and controlling costs of the nuclear submarine programme to keep open options prior to a decision being taken, but did not include further details.[95]

115. It is important that the Government continue to invest in the UK infrastructure and skills base until a decision on whether to retain or abolish the nuclear deterrent is made. Unless this investment is forthcoming, the Government is likely to find that its options will be constrained and that certain choices for the future of the UK's nuclear deterrent will no longer be available.

The timetable for decision-making

116. The timing of decisions on the future of the UK's strategic nuclear deterrent is dictated by the time involved in extending, upgrading or replacing the three distinct components of the current Trident system: the warhead, the missile and the platform.

117. The UK's strategic nuclear deterrent "is a system of systems", including the warhead, the missile, the submarine, and the supporting infrastructure. Extending, upgrading or replacing these components represent the timeline challenges which are driving the current debate on the future of the UK's nuclear deterrent.[96]


118. The UK's current nuclear warhead, based on the American W76 design, which is fitted to the Trident II D5 missile, was introduced into service with the Trident system in 1994. It is widely expected to remain in service until the mid-to-late 2020s. The MoD itself has stated that:

119. The MoD's new investment programme at the Atomic Weapons Establishment amounts to an additional £350 million per annum over the next three years. This programme indicates that the Government is already examining the research, capability and stockpile issues relating to the nuclear warhead. It does not necessarily mean that the MoD has already decided to continue with a strategic nuclear deterrent programme. The MoD itself has explained the purpose of the Aldermaston investment as necessary to keep its options open for the future:

    This additional investment at AWE is required to sustain the existing warhead stockpile in-service irrespective of decisions on any successor warhead. The investment will sustain core skills and facilities that could also be used in future to develop a successor but no decisions have yet been made either in principle or practice on this issue.[98]

120. During our visit to the United States in May 2006, we heard that the US had embarked on a Reliable Replacement Warhead programme (RRW), aimed at modernising the US strategic nuclear arsenal and improving the reliability, performance, longevity and safety of US nuclear weapons. Managed by the National Nuclear Security Administration at the Department of Energy, the programme represents a shift in design philosophy for the American strategic stockpile. During the Cold War, the priority in US warhead design was on limiting the weight and size of the warhead for improved delivery while maximising its yield. Given the change in the strategic environment since the end of the Cold War, we were told that such considerations were no longer paramount and that the focus was now on making the warheads more straightforward and cost-effective to manufacture and maintain. We heard that the RRW programme was in its early stages, that two designs were in preparation, that one of the two designs would be selected in late 2006, and that the new warhead was expected to enter service in the 2010 to 2015 timeframe. The UK's MoD has not announced a similar programme for its Trident warheads. However, the new investment programme at Aldermaston addresses similar issues of reliability, performance, longevity and safety of the UK's existing warheads.

121. Given the new investment at Aldermaston, and the widespread expectation that a new warhead will not be required until well into the 2020s, the timelines for manufacturing a replacement warhead is not a key driver of the current debate.


122. The current Trident II D5 missile entered service with the rest of the UK's Trident system in 1994 and had a planned life of around 25 years. The UK has title to 58 such missiles which are held in a communal pool at King's Bay, Georgia.

123. In 2002, the United States Navy awarded Lockheed Martin a contract for the Trident II D5 missile Service Life Extension Programme (SLEP). Under the contract, it is expected that around 300 missiles will be upgraded to the D5(A) version by 2020 and that these upgraded missiles will remain in service until 2042. According to Jane's Missiles and Rockets, the Trident II D5 Service Life Extension Programme is not envisaged as "a major design, but would involve the replacement of specific components, especially those that are dependent on older technologies which in many cases are no longer being manufactured".[99] The United States has also launched a service life extension for the Mk4 re-entry vehicle, which carries the nuclear warheads, in order to support Trident operations until 2042. The UK Government has yet to decide whether or not to participate in this service life extension programme. We were told that it would be relatively easy for the UK to participate in the Trident II D5(A) life extension programme on the same basis as it participates in current arrangements.

124. Since the Trident II D5 missile will be in service in the United States until 2042, this component of the system is not a key driver of the current debate.

125. During our visit to the United States in May 2006, we were told that the US was unlikely to make decisions on the future of its strategic nuclear deterrent before the middle of the next decade at the earliest. The US Service Life Extension Programme implies that American decisions may be made even later. Assuming the same 14 year procurement timeframe, the US might, in fact, not need to made decisions on the future of its deterrent until the mid-2020s. The disjunction between the US and UK timeframes poses difficulties for the UK. In making a decision on the potential replacement of the current system, the UK will need to make sure it does not opt for a system to which the US is only committed until 2042. As the experience of Polaris Chevaline in the 1970s indicated, maintaining a system which is not in service in the US carries significant cost implications.


126. The platform is generally regarded as the crucial factor driving the current debate on the future of the UK's strategic nuclear deterrent.

127. In evidence to us, Dr Lee Willett stated that "one of the key points in this whole timeline debate is the issue of the submarine. The submarine is the big platform, the big question in the replacement debate".[100] Dr Willett's judgement, that the submarine was the critical factor in driving the current consideration of the future of the UK's strategic nuclear deterrent, was widely shared amongst the witnesses to our inquiry.

128. The UK's Vanguard-class SSBN Trident submarines were introduced into service over a six year period beginning in December 1994. They were procured with a designed operational life of 25 years. On this basis, they would start to be withdrawn from service from late in the next decade; HMS VANGUARD, HMS VICTORIOUS, HMS VIGILANT and HMS VENGEANCE, which entered service in December 1994, December 1995, June 1998 and February 2001 respectively can be expected to be withdrawn in 2019, 2020, 2023 and 2026.[101]

129. In order to maintain the Continuous-at-Sea Deterrent cycle (CASD), the MoD has stated that the Royal Navy must maintain a minimum fleet of four SSBN submarines. This means that in 2019, when HMS VANGUARD is likely to leave service, CASD can still be maintained. It is the withdrawal of HMS VICTORIOUS, a year later, that will affect the ability of the Royal Navy to maintain CASD.

130. If the MoD believes that the UK should retain the Continuous-at-Sea Deterrent cycle, it must either extend the life of the Vanguard-class submarine or procure a new platform to be in service by 2020. In the light of the reduced threat we currently face, an alternative possibility would be to retain a deterrent, but not continuously at sea.

131. The MoD has stated that it may be possible to extend the service life of the current Vanguard-class fleet:

    A series of studies have considered whether it would be practical and cost effective to continue to operate the submarines beyond the original design intent. We now believe that, if required, this would be possible, albeit with gradually increasing cost and some increasing risk of reduced availability, perhaps out to the mid-2020s.[102]

132. The MoD has not stated exactly what a Service Life Extension Programme (SLEP) for the Vanguard-class submarine would involve. In evidence to us, Dr Lee Willett stated that the key factor limiting the life of the submarine is the durability of the hull and of the reactor. He also told us that the UK has a very stringent set of safety measures which limit the life of the reactor to 25 years.[103] Commodore Tim Hare told us that "to renew that safety justification is a non-trivial activity…it can be done, but…not for much more than five or six years".[104] Peter Whitehouse, of Devonport Management Ltd, argued that:

    In terms of the life of the nuclear steam raising plant, [the projected life span] is an inherent function of the design features, metallurgy and duty cycle when the system is in use. Once the Vanguard-class has had its series of first refits the fuel life is not an issue because the fuel will be good for another 20 to 25 years. Within the MoD experience has been that the older classes of submarine have become less and less available and reliable because of reactor system issues in a third commission; in other words, beyond the 20-year point. One key issue is the extent to which the Vanguard-class reactor plant, which is a totally new generation plant, has inherently the same design features and issues that could cause problems and a loss of availability towards the end of a second commission.[105]

133. Mr Whitehouse also told us that in a second refit of the Vanguard-class submarines "major systems within the non-nuclear components of the submarine itself would have to undergo major overhaul".[106] He stated that this kind of refit could be carried out from the middle of the next decade, from around 2015.[107]

134. The United States has already approved a service life extension programme of its Trident submarines, the Ohio-class SSBN. As a result of this programme, the American boats are expected to remain in service until 2042, the same date as the life extended Trident II D5(A) missile.

135. The decision of the US to extend the service life of its Trident boats raises the possibility of the UK embarking on a similar programme. This could offer the UK an opportunity to maintain the Continuous-at-Sea deterrent cycle in the short term.

136. In the longer term, the possession of a strategic nuclear deterrent will depend upon the procurement of a new platform. This is expected to require a significant lead-time. The procurement time for the Vanguard-class submarine, from the point of initial decision to the in-service date, was 14 years. The procurement timeframe might be less in a new generation of submarines but it might be prudent to assume a 14 year norm. On this assumption, an initial decision point for a potential successor SSBN submarine would be 2010, if the Vanguard-class underwent a limited refit.


137. Peter Whitehouse told us that retention of the onshore infrastructure and skills base was a key consideration in the debate over the future of the UK's strategic nuclear deterrent. He argued that unless further investment is made to sustain the onshore infrastructure and skills base in the UK, at Devonport, Barrow-in-Furness and Aldermaston they would be lost and would be difficult, perhaps impossible, to reconstitute. He stated that until the Government makes a decision on the future of the UK's strategic nuclear deterrent, it must continue to invest in these facilities so that it retains the full spectrum of choices on what to do post-Trident. If this investment is not forthcoming, he argued, the Government is likely to find that certain options are no longer available.

138. We believe that the maintenance of onshore infrastructure and the domestic UK skills base is an issue of paramount importance in considering the future of the UK's nuclear deterrent. We have decided that this will be the focus of the next in our series of inquiries into the future of the strategic nuclear deterrent. In that inquiry we will also address the linkage between the Government's Defence Industrial Strategy and the decision on retention, replacement, or abolition of the UK's Trident system.

92   Ev 67 Back

93   Main Gate is the approval point between the Assessment Phase and the Demonstration and Manufacture Phases Back

94   Q 170 [Commodore Hare] Back

95   Ministry of Defence, The Defence Industrial Strategy, December 2005, Cm 6697, p 76 Back

96   Ev 69 Back

97   HC (2005-06) 835, Annex B, para 2(a) Back

98   Ibid., Annex C, para 13 Back

99   'US navy to extend life of Trident force,' Jane's Missiles and Rockets, 1 September 2000 Back

100   Q 53 [Dr Willett] Back

101   HC (2005-06) 835, Annex B, para 2(c) Back

102   Ibid. Back

103   Q 61 Back

104   Q 170 [Commodore Hare] Back

105   Ibid. Back

106   Q 170 [Mr Whitehouse] Back

107   Ibid. Back

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