Select Committee on Defence Ninth Special Report

Appendix: Government response


1. The Government is pleased to present its response to the House of Commons Defence Committee's Eighth Report of Session 2005-06 on the Future of the UK's Strategic Nuclear Deterrent.

MOD Engagement

We welcome the Government's promise of a full and open debate in Parliament and in the country at large, on the future of the UK's strategic nuclear deterrent. We are surprised and disappointed that the Ministry of Defence has refused to participate in our inquiry. We believe that a genuine and meaningful debate is only possible with the active participation of the MOD. We call upon the MOD to engage fully in our forthcoming inquiries into the future of the UK's strategic nuclear deterrent. We hope the MOD will make a substantive response to this report and that it will address openly the issues we have raised. (Paragraph 12)

2. The Ministry of Defence does not accept these criticisms. We are disappointed that the Committee chose in its report not to recognise the substantive contributions that we made to its considerations. We provided an initial memorandum in November 2005, setting out the expected life of the current system, the possible legal constraints on our decision-making and more detail on the programme of investment at the Atomic Weapons Establishment, Aldermaston. The then Defence Secretary also covered this issue in some detail during his introductory session with the Committee on 1 November 2005. We also wrote to the Clerk of the Committee on three occasions (on 26 September 2005, 24 November 2005 and 29 November 2005) indicating the limitations on the information that could be made available in support of an early inquiry, given that work by officials on this issue was then at a very early stage and that Ministers had not yet become involved. The timing of the inquiry was for the Committee to decide, but this made it difficult for the Department to meet all of the Committee's requests for information.

3. We will continue to do all we can to support future inquiries by the Committee in this area. This document aims to provide the substantive response to the report which the Committee requested.

4. The Government has promised a full debate on this issue and the publication of a White Paper. We have also made clear that decisions will be taken this year. The means of consulting Parliament will be made clear when we publish the White Paper.

The Size of the UK's Nuclear Arsenal

The UK's strategic nuclear arsenal is small in comparison with the other established nuclear powers. (Paragraph 45)

5. The MOD agrees that the UK's strategic nuclear arsenal is small in comparison with the other established nuclear powers. This comparison is, however, not necessarily a useful one, as the UK pursues a strategy of minimum nuclear deterrence. We do not see Trident as a weapon system for fighting wars, but as having a fundamentally political role in deterring aggression. We would only ever contemplate its use in extreme circumstances of self-defence. The extent of our nuclear capabilities is therefore maintained at the minimum level required to deter aggressors, rather than by the number of warheads held by other countries.

6. The UK has an extremely good record of meeting our obligations under the Nuclear Non-Proliferation Treaty. Since the end of the Cold War we have:

  • withdrawn and dismantled the RAF's WE177 nuclear bomb without replacement, so that Trident is our only nuclear weapons system. The UK is the only Nuclear Weapon State to have reduced to a deterrent based on a single platform, a single delivery system and a single warhead design.
  • dismantled all of our remaining Chevaline (Polaris) warheads demonstrating our commitment to irreversible reductions in the UK's nuclear weapons.
  • reduced our operationally available stockpile of nuclear weapons to fewer than 200 warheads, (a 70% reduction in the potential explosive power of our nuclear forces since the end of the Cold War).
  • reduced the readiness of our nuclear forces. Only one Trident submarine at a time is on deterrent patrol, carrying 48 warheads (compared to a previously planned total of 96), normally on several days' "notice to fire". Its missiles are not targeted at any country.

7. We noted one minor error in the report on this subject. It is not the case (as stated in para 38 of the report) that the Strategic Defence Review stipulated that no more than 3 warheads would be fitted to each UK Trident D5 missile or that the precise number of warheads carried on patrol at any given time remains classified. The SDR in fact said simply the following:

"We will have only one submarine on patrol at a time, carrying a reduced load of 48 warheads." (SDR Chapter 4 Para 67)

The role of the Nuclear Deterrent

In considering the future of the strategic nuclear deterrent, the UK will need to examine whether the concept of nuclear deterrence remains useful in the current strategic environment and in the context of the existing and emerging threats to the security of the country. We will have to consider whether those states and non-state actors posing such threats can, in reality, be deterred from instigating acts of aggression by either existing or new approaches to nuclear deterrence. We will also have to consider how the UK's nuclear capability should be adjusted to meet new strategic realities. Trident was developed during the final decade of the Cold War, and was designed to counter the threat posed by the size and technical capabilities of the Soviet strategic nuclear arsenal: we need to consider whether the form of the UK's current nuclear deterrent is best suited to today's and tomorrow's strategic challenges. (Paragraph 55)

We believe that it is essential that, before making any decisions on the future of the strategic nuclear deterrent, the MOD should explain its understanding of the purpose and continuing relevance of nuclear deterrence now and over the lifetime of any potential Trident successor system. (Paragraph 56)

8. The Department notes these conclusions. In terms of the current system and current security threats, the Strategic Defence Review considered carefully the relevance of nuclear deterrence in the post-Cold War world. It concluded that:

"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."

9. The SDR did, however, lead to some reductions in the scale of our nuclear capabilities, as set out in our response to Conclusion 2 above.

10. Work is currently underway by officials to consider the potential role of the UK strategic nuclear deterrent over the lifetime of any potential successor system. The White Paper will set out the conclusions of our analysis on future risks and threats, the extent of any enduring requirements for a minimum nuclear deterrent, the possible options and costs.

International Impact

Before any decisions on the future of the deterrent are made, it will be important to consider whether the possession of nuclear weapons enhances the UK's international influence and status and whether this contributes to the justification for retention of a strategic nuclear capability. (Paragraph 57)

It is clear that there is a difference of views and no clear consensus that international influence is, of itself, a reason to retain the strategic nuclear deterrent. We recommend that the MOD make clear whether the Government believes the possession of a nuclear deterrent is an important contributor to the UK's international influence. (Paragraph 65)

11. We maintain the current nuclear deterrent, not because of the status it gives us, but because of its role in deterring acts of aggression, in insuring against the re-emergence of major strategic military threats, in preventing nuclear coercion, and in preserving peace and stability. We will set out more fully the factors we believe are relevant to the current and any possible future minimum nuclear deterrent by the UK when we publish a White Paper.


The public debate over the future of the UK's strategic nuclear deterrent should address:

  • the independence of the UK's current system; and
  • the operational and diplomatic impact of any potential dependency on the United States of any future UK nuclear deterrent. (Paragraph 66)

It is important to distinguish between two different types of independence: independence of acquisition and independence of operation. We heard that independence of acquisition is what the French have opted for at a significantly higher cost to the defence budget. Independence of operation is an alternative concept of independence and it is this which the UK has opted for at a lower price. (Paragraph 80)

We call upon the MOD to clarify the technical dependencies of the UK's Trident system upon the United States and to respond to the argument that the UK's nuclear deterrent is not truly independent. In weighing the importance of maintaining independence, attention needs to be paid to the differing concepts of independence adopted by the UK and France. (Paragraph 84)

12. The Department notes these remarks and we would disagree with much of the evidence given to the Committee on this question. In terms of the current system, as we have made clear on many occasions, 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. The instruction to fire would be transmitted to the submarine using entirely UK codes and UK equipment. All the command and control procedures are totally independent. The Vanguard-class submarines can readily operate without the Global Positioning by Satellite (GPS) system and the Trident D5 missile does not use GPS at all: it has an inertial guidance system. We would require no lesser degree of operational independence for any successor system should the Government decide to replace Trident.

Future Threats

The public debate about the future of the UK's strategic nuclear deterrent must take into account:

  • the nature of the threats facing the UK;
  • how these threats could evolve over the lifetime of any potential Trident successor system; and
  • in what ways retention of a strategic nuclear deterrent might assist the UK in addressing these threats. (Paragraph 85)

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. (Paragraph 88)

Witnesses to our inquiry did not believe that the UK currently faced a direct or impending military threat from any of the established nuclear weapons states, including Russia, China, India, Pakistan, Israel, North Korea, or, of course, from France or the United States. (Paragraph 95)

There are difficulties inherent in anticipating future threats to the security of the UK. It is not possible to predict accurately the nature of the future strategic international environment and to identify with any certainty the threats the UK is likely to face. (Paragraph 96)

We call upon the MOD to consider publicly the threats the UK faces today and how those threats may evolve in the future. Such a threat assessment will shape any decision on the future of the UK's strategic nuclear deterrent. We accept that future threats are unknowable, but, clearly, a world in which nuclear proliferation had taken hold would create deep uncertainties in international relations. For this reason, the UK may wish to retain a strategic nuclear capability as a guard against the unknown. If the MOD believes in the value of the nuclear deterrent as an insurance policy, rather than in response to any specific threat, we believe it is important to say clearly that this is the reason for needing the deterrent. (Paragraph 103)

13. The debate about the future of the UK's nuclear deterrent is less about the security position now than about the extent to which we can be confident about the nature of the risks and threats to our defence and security interests that we might face over the next 20-50 years

14. Our overall assessment of potential long-term security challenges will be set out in a paper on the future strategic context, which is due to be published by the MOD later this year. We will set out the conclusions of our analysis of the risks and threats over the period directly relevant to our nuclear deterrent capabilities, and therefore any replacement for the Trident system, in the forthcoming White Paper.

Timetable for Decisions

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. (Paragraph 104)

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. (Paragraph 106)

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. (Paragraph 110)

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. (Paragraph 121)

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. (Paragraph 124)

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

15. The Department notes these conclusions and recommendations. In the memorandum forwarded to the Committee in November 2005, the Department made the following comments on the expected life of each element of the current system:

a) The Warhead:

The current warhead came into service with the Trident system in 1994. An extensive research programme to assure the safety and effectiveness of the warhead stockpile, coupled with the additional investment at AWE Aldermaston announced on 19 July 2005, gives a high level of confidence that the current warhead design can, if required, be maintained in service at least into the 2020s, with some relatively minor upgrading and refurbishment during the first half of the next decade.

b)  The Ballistic Missiles:

The Trident D5 missile came into service with the Royal Navy in 1994, with a planned life of some 25 years. The US Navy has recently announced plans for a life extension programme for the D5 missile, which will ensure it can remain in-service with the US Navy into the 2040s. The UK Government has yet to decide whether or not to participate in this programme.

c)  The Submarines:

HMS VANGUARD entered operational service with the Royal Navy in 1994, with the other three submarines in its class following in 1995, 1998 and 2001. The submarines were procured with a designed operational life of 25 years and on this basis, they would start to be withdrawn from service late in the next decade. A series of studies have considered whether it would be practicable 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.

16. The time-table for decision making is driven by the life span of the current system and the lead-time that would be required for the acquisition of any replacement. Given our assessment of the time it might take to develop any replacements, we believe the key decisions that are required in the near term relate to:

a)  participation in the life extension programme for the Trident D5 missile; and

b)  extension of the life of, and any replacement for, the Vanguard-class submarines.

17. Other decisions will be necessary beyond this point. The background to this position will be set out in more detail in the White Paper. We do not share the assessment, set out at conclusion 17 of the report, that extending the life of the Vanguard-class submarines means that we can postpone decisions on any replacement for the Vanguard class submarines until around 2010. We believe that it would be imprudent to assume that any successor to the Vanguard-class could be designed, procured and deployed within 14 years.

Skills and Infrastructure

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 viable. (Paragraph 115)

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. (Paragraph 138)

18. The Department remains committed to keeping options open in advance of decisions on the future of the deterrent. The Defence Industrial Strategy states that for the foreseeable future we will retain on-shore:

"all of those capabilities unique to submarines and their Nuclear Steam Raising Plant, to enable their design, build, support, operation and decommissioning".

The Department has therefore funded work to sustain submarine design capability across a broad range of industrial and technology areas, including BAE Systems and Rolls Royce design teams. For example, the need to maintain key skills in the area of nuclear propulsion is being addressed through focused work aimed at addressing both current fleet issues as well as the planned and any potential future submarine programmes.  Some £20M was invested last year in Rolls-Royce and other key partners in this respect and we anticipate investing similar sums this year and next.

19. Furthermore, as we announced in July 2005, we are making an additional investment averaging around £350M per year over each of the three years to 2007/08 at the Atomic Weapons Establishment. This investment is aimed at sustaining facilities and skills that are required to maintain the safety and effectiveness of the current Trident warhead stockpile without recourse to nuclear testing, in compliance with the Comprehensive Nuclear Test-Ban Treaty and also to keep options open for the future.

20. We note and welcome the Committee's intention to make these and related issues the focus of the next stage of their inquiry into the Strategic Nuclear Deterrent.

Deterrent Posture

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. (Paragraph 130)

21. The question of the operational posture of the existing UK nuclear deterrent was considered in detail during the Strategic Defence Review. It was then concluded that:

"ending continuous deterrent patrols would create new risks of crisis escalation if it proved necessary to sail a Trident submarine in a period of rising tension or crisis. This is a particular concern given our reduction to a single nuclear system. It could force a government into earlier and hastier decision making if strategic circumstances were to deteriorate. Either step would undermine the stabilising role that Britain's nuclear deterrent forces would otherwise play in a developing crisis".

22. The posture to be adopted by any successor system will need to be considered carefully against our perceptions of the operational requirement. This will be addressed in the White Paper to be published following the decisions to be taken later this year. However, the ability of any deterrent system to survive pre-emptive action by an adversary is likely to remain an important aspect of its credibility.

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