Select Committee on Defence Ninth Report


7  Deterrent options and costs

Deterrent options

Table 7: The Government's assessment of deterrent options
Option  The White Paper's assessment 
Air-based system equipped with cruise missiles  Vulnerable to pre-emptive attacks  
 Increasing readiness would be visible and potentially escalatory in times of crisis  
 Need to procure a new aircraft  
 Need to procure a new missile  
 Need to develop a new operating base  
 The most costly option of all  
Land (silo)-based system  Vulnerable to pre-emptive attack; immobile and impossible to conceal  
 Need to acquire new land covering several hundred square kilometres - impractical in the UK  
 Need for an expensive command and control system  
 Costs are twice those of a submarine option  
Ship-based system equipped with Trident ballistic missiles  Vulnerable to pre-emptive attack; easier to detect and track than a submarine  
 Less capable than a submarine-based option  
 Need to develop on-shore infrastructure  
 Similar in cost to a submarine-based option  
Submarine-based system equipped with Trident ballistic missiles  An SSBN is undetectable  
 It is the most cost-effective platform  
 It can be deployed covertly and have a deterrent effect anywhere in the world  
 The UK already has a functioning submarine construction and support infrastructure  
Submarine-based system equipped with cruise missiles  Need for a much greater number of submarine hulls, including SSNs  
 Need to develop a new cruise missile  
 Lack of range and greater vulnerability  


128. In the White Paper, the Government states that "before arriving at decisions, we undertook a thorough review of the widest possible range of options to replace the Vanguard-class submarines". It says that it "used a detailed assessment process to narrow the range of options under consideration". The White Paper considers "four generic options": a large aircraft equipped with cruise missiles; silo-based ballistic missiles; a surface ship equipped with Trident missiles; and, a submarine equipped with Trident missiles. [170]

129. It rejects the large aircraft option "primarily because of vulnerability to pre-emptive attacks and because of the costs involved in procuring new large aircraft and the supporting refuelling tankers, providing new infrastructure, and designing and procuring a new cruise missile". The White Paper says that an air-based option was "the most expensive and by some distance the least capable option".[171] It rejects a silo-based system on the grounds that it would be a credible deterrent "only against states with a limited nuclear capability" and because of "the significant additional costs compared to a submarine-based system capable of deterring all credible threats". It concludes that a land-based option "presented some major practical difficulties, especially in terms of vulnerability" and it argued that "the through life costs were around twice those for a submarine option".[172] The White Paper rejects a ship-based system because it "would be less capable, more vulnerable and no less expensive than a submarine-based solution".[173] It also rejects the option of a cruise missile delivery system on the grounds that developing a new missile "would cost far more than retaining the Trident D5 missile" and because "in capability terms, cruise missiles are much less effective than a ballistic missile".[174]

130. The White Paper concludes that "from a capability perspective…a submarine-based system offers the most practical and effective means of meeting our future nuclear deterrent requirements". It stated that it was also the most cost-effective solution.[175] It concludes that "in terms of cost and capability, retaining the Trident D5 missile is by far the best approach".[176]


131. None of the witnesses to our inquiry was surprised the Government had decided to opt for a renewal of the submarine-based deterrent. Few of them considered the SSBN option was the wrong one. But, of course, a great many of them argued that the Government was wrong to renew the nuclear deterrent at all, and a few thought the Government's justification for its choice was inadequate.

132. Dr Jeremy Stocker, of the IISS, told us that the decision was "a no-brainer" and that it was "very difficult to fault the logic of the White Paper".[177] He argued that "a pretty comprehensive study has been done, based on realistic assumptions and the conclusions are correct".[178]

133. RUSI witnesses too endorse the Government's decision. In written evidence to our inquiry, they state that "the fundamental principle for an effective deterrent is a survivable platform and weapon system which can delivery the desired effect and the place and time of choice, holding at risk anything which a potential adversary may value". They conclude that "only a submarine-based system deployed in CASD cycle can deliver this guarantee" and that "none of the other options addressed in the White Paper would provide the requisite strategic capability, nor would they be more affordable".[179] Professor John Baylis, of the University of Swansea, agrees and states that "surviving pre-emptive actions remains a critical part of contemporary deterrence and consequently there do not appear to be strong arguments to diverge from this formula".[180]

134. Some witnesses to our inquiry challenged aspects of the Government's assessment. Dr Andrew Dorman, of King's College London, argues that the White Paper fails to explore the possibility of having a submarine fleet equipped with nuclear-armed cruise missiles. He questions the Government's assumption that the UK would need to develop a new missile and sees no reason why the Tomahawk cruise missiles carried on the UK's SSN fleet could not be adapted to carry a nuclear warhead in place of their conventional warhead.[181] Although he is supportive of the Government's assessment of the options, this omission is also noted by Jeremy Stocker. Submarine-launched cruise missiles, he suggests, would be "the most credible or attractive alternative" to the Trident force. However, on balance, he accepts the Government's argument that cruise missiles lack the range and invulnerability offered by Trident ballistic missiles.[182]

135. In its memorandum of 1 February 2007, the MoD states that the White Paper "represented a high level summary of a great deal of work, much of which is necessarily highly classified". On the issue of cruise missiles versus ballistic missiles, it argues that "in both cost and capability terms, retaining the Trident D5 missile is by far the best approach". It suggests that "a much larger number of cruise missiles, compared to Trident D5 missiles, would be required to meet our minimum deterrence requirements". And it says that "moving to a deterrent based on submarine-launched cruise missiles could well lead to a requirement for additional submarine hulls".[183]

136. Dr Dorman also criticises the Government's assessment of an air-based nuclear deterrent. He suggests that "the civilian airliner option makes a number of assumptions that seem designed to inflate the cost". In particular, he asks

why would a new air base need to be built?...why does the cruise missile have to be a new one?...why does the platform have to be a new civilian airliner?...why has the range requirement risen so sharply compared to the existing Trident force or its predecessors…[and] what compensatory savings would result from the Royal Navy shifting away from nuclear powered submarines?[184]

With such questions unanswered, Dr Dorman concludes that "there is a good deal of smoke and mirrors in these options and their associated costings".[185]

137. The Secretary of State told us that only a submarine-based deterrent was sufficiently invulnerable to pre-emptive attack. He said that although many experts had long predicted that the oceans would become transparent, this has not come to pass. The White Paper states that

We have assessed carefully the potential for future developments in anti-submarine warfare to compromise [the submarine's] position. We believe it is unlikely there will be any radical technological breakthrough which might diminish materially the current advantages of a submarine over potential antisubmarine systems…we judge that a submarine will remain by far the least vulnerable of all the platform options considered.[186]

Mr Browne told us that "none of our submarines have ever been detected" and that the threat of detection "has been identified for some time now and has not become a reality". Given that all other options were far more vulnerable to pre-emptive attack, Mr Browne said the submarine "is still the best option".[187]

138. While many of our witnesses disagreed with the Government's decision to renew the nuclear deterrent, few challenged its choice of a submarine-based ballistic missile over other deterrent options. However, some have found the analysis of the options in the White Paper not to have explored fully the option of a nuclear-powered submarine carrying cruise missiles, noted as being the best alternative option. The Government should set out in more detail what were the comparative advantages of cost, range, operation and invulnerability associated with cruise and D5 missiles which led them to conclude in favour of the D5 missile. We believe the Government should offer further details of its assessment of deterrent options.

Costs and funding

Table 8: The costs of renewing the deterrent
Cost item  The Government's cost estimate 
Vanguard-class 5 year life extension  "hundreds of millions"  
Overall procurement costs  £15-20 billion 
Of which: submarines   £11-14 billion  
Warhead refurbishment/replacement   £ 2-3 billion  
Submarine infrastructure   £ 2-3 billion  
In-Service costs (capital and running costs)  £1.5 billion a year  
Decommissioning costs   
Nuclear submarines (both SSNs and SSBNs)  £837 million 
Shore infrastructure  [unclear - MoD total nuclear liabilities accounted for at £9.75 billion]  
Trident D5 missile life extension programme  £250 million 
New missile  [unknown - Trident D5 cost £1.5 billion]  

139. The costs of renewing the UK's strategic nuclear deterrent reflect the costs of: extending the life of the current Vanguard-class submarine; designing and manufacturing a replacement SSBN; participating in the US Trident D5 missile life extension programme; participating in a future Trident D5 replacement programme; and, refurbishing or replacing the UK's nuclear warheads. There will also be costs associated with the maintenance of onshore infrastructure and of decommissioning retired submarines and warheads as well as the personnel costs of operating the system and its supporting infrastructure.

140. The White Paper estimates that "once the new fleet of SSBNs comes into service, we expect that the in-service costs of the UK's nuclear deterrent, which will include AWE's costs, will be similar to today (around 5-6% of the defence budget)".[188] It also pledges that "the investment required to maintain our deterrent will not come at the expense of the conventional capabilities our armed forces need".[189]


141. The White Paper does not offer any details on the projected cost of extending the life of the Vanguard-class submarine. It merely states that any attempt to extend the life beyond 30 years "would not…be cost effective".[190]

142. We asked the Secretary of State for Defence how much it would cost to conduct a five-year life extension of the Vanguard-class submarine. In response, Tom McKane, Director General Strategic Requirements at the MoD, told us that "detailed costings of that life extension will be generated as we get closer to the point where work actually has to be done on the boats".[191] However, he stated that "the work that we have done shows that we are probably talking in round terms of hundreds of millions for the five years for the four boats". Mr McKane told us that with life extension beyond 30 years "you then start talking in terms of billions".[192]


143. The White Paper states that the Government's "initial estimate is that the procurement costs will be in the range of £15-20 billion (at 2006/07 prices) for a four-boat solution". This is made up of "some £11-14 billion for the submarines; £2-3 billion for the possible future refurbishment or replacement of the warhead; and £2-3 billion for infrastructure over the life of the submarines". It also states that the "comparable cost for the Trident system was some £14.5 billion at today's prices," which, the White Paper argues, is "also comparable to the procurement costs of major weapons systems such as Typhoon aircraft".[193] The White Paper emphasises that these costs are estimates and that they "will need to be refined as work on the concept and assessment phases is taken forward with industry". And it says that "more accurate cost estimates will be available by the time we come to place a contract for the detailed design of the submarines in the period 2012 to 2014".[194]

144. Some witnesses to our inquiry questioned the cost estimates put forward by the Government. Dr Jeremy Stocker, for example, says that while "the sums entailed are relatively trivial" in relation to overall public expenditure, "the cost of the new submarines seems very high". He argues that the current fleet of Vanguard-class submarines cost "a little under £6 billion" at 2004/05 prices. The figure of £14.5 billion cited in the White Paper, he argues, was for the cost of the entire Trident programme, the missiles, warheads and the submarines together. This would appear to be in line with the 1998 Strategic Defence Review, which estimated "the total cost of acquiring the Trident system to be about £12.5 billion".[195]

145. Dr Stocker suggests that the costs projected in the White Paper "may reflect experience with the Astute programme and the fact that with a smaller overall submarine force individual units cost more". But he notes that "there is…a determination in the MoD not to underestimate costs as any later over-runs would be at the expense of the rest of the equipment programme".[196]

146. We asked the Secretary of State for Defence whether he could offer further clarification on the costs of procuring a new SSBN. Mr Browne told us that the cost estimates in the White Paper "are the best estimates we can give…these are honest assessments". He accepted that as the costs become clearer "we will have an obligation…to keep Parliament and others informed about that development".[197] But he maintained that "as a country, we have a very good track record of building these SSBNs and in fact the current class of submarines came in on time and under budget".[198] Mr McKane noted that the estimates "have been done carefully to ensure that they do include a range…and that the range contains contingency".[199]

147. The White Paper states that "the investment required to maintain our deterrent will not come at the expense of the conventional capabilities our armed forces need". It says that "decisions on the level of our investments in nuclear and conventional capability will be taken in the Comprehensive Spending Review, the results of which will be announced next year".[200] In evidence, the Secretary of State told us that "this investment will be maintained not at the expense of the conventional capabilities of our Armed Forces…I cannot give any clearer reassurance than that."[201]

148. We welcome the Government's assurance that funding for the nuclear deterrent will not come at the expense of the conventional capabilities required by the UK's Armed Forces. However, the Government has not said how it would guarantee this, when expenditure on the deterrent is included in the defence budget. We call on the Government to specify in more detail how it will fulfil this assurance. It is important that additional funding is provided not only for the initial procurement costs, but also with any additional costs of maintaining the system in-service.


149. The White Paper states that "once the new fleet of SSBNs comes into service, we expect that the in-service costs of the UK's nuclear deterrent, which will include AWE's costs, will be similar to today (around 5-6% of the defence budget)".[202]

150. Some witnesses to our inquiry suggested that that these costs were higher than the UK's current expenditure on the deterrent: they stated that the 1998 Strategic Defence Review envisaged the costs of the deterrent to be only around 3% of the defence budget. RUSI argues that the White Paper's reference to the future running costs of the nuclear deterrent "is in contrast to previous statements, which have detailed a running cost of between 2 and 4% since 1997".[203]

151. The SDR stated that

we estimate that the running cost of the Trident submarine force will average some £280M a year over its life time. The annual cost of our warhead and fissile material programme is some £400M a year. About one third is directly related to Trident, almost a third is related to costs arising from previous nuclear weapons and the remainder is infrastructure costs.[204]

The SDR said that "these are very substantial costs but need to be seen in perspective. The annual cost (including the continuing costs from earlier programmes) is little more than 3% of the defence budget. This is not a disproportionate investment in a capability of such vital importance to our national security".[205]

152. In its memorandum of 19 February 2007, the MoD states that "the annual expenditure on capital and running costs of the Trident nuclear deterrent, including the costs of the Atomic Weapons Establishment (AWE), is expected to be between 5 and 5.5 % of the defence budget". It says that this estimate "was based on the planned near cash defence budget of £28,700 million in 2006/7" and that actual "annual expenditure would be around £1,500 million".[206]

153. It is important that Parliament be aware of the full costs of retaining and renewing the UK's nuclear deterrent before it is asked to agree to the Government's proposals. These costs include not only the acquisition costs for a new fleet of SSBNs, but also the costs of life extension, the costs of the missile and warhead programmes, the projected infrastructure costs, and the personnel costs of operating and maintaining the deterrent. The Government says that the overall procurement and infrastructure costs are £15-20 billion and that the annual running costs will be £1.5 billion at 2006-07 prices.

154. The MoD proposes to embark on a life extension programme for the current Vanguard-class SSBNs, but has not offered a clear estimate of the costs involved in that programme. The MoD should make it clear when it will be in a position to give more accurate estimates and what work needs to be done to achieve this.


155. The House of Commons should be aware that, even if it were to vote against retaining the deterrent, certain costs would be involved. These would include costs, such as onshore infrastructure, industrial costs, and regional assistance to the areas affected by industrial closures. The costs of investing in regions affected by any decision not to go ahead with renewal of the present deterrent should be estimated and included together with other costs so that those who argue there is an opportunity cost to other public expenditure can see what the full costs of such a negative decision are.


156. We asked the MoD for an estimate of the likely decommissioning costs of the Vanguard-class SSBN in the event that a decision to abandon the nuclear deterrent was taken.

157. In its memorandum to us of 19 February, the MoD told us that "it is not possible to provide a precise estimate of the costs that would be incurred in decommissioning the four Vanguard-class submarines in [such] hypothetical circumstances". However, it stated that

the MoD has made provision in its forward plans for the decommissioning of the Vanguard-class submarines, and other in-service submarines, when they reach the end of their planned operating lives. These plans, together with provision for the berthing and decommissioning of our of service submarines, are reflected in the £9,753,827,000 undiscounted nuclear liabilities, stated in the MOD Annual Report and Accounts for 2005-06 (HC 1394). £837 million is included for the decommissioning of submarines, up to and including Vanguard-class.[207]

158. In its response to our second-stage report on the future of the UK's nuclear deterrent, the MoD said that its "strategy for de-commissioning nuclear-powered submarines is currently under review in light of the revised project proposals for de-fuelling facilities and the 2006 report of the Committee on Radioactive Waste Management".[208] It also stated that "financial provision for the de-commissioning of past and current SSNs and SSBNs is included in the MoD Accounts" and "amounts to some £1.75 billion of undiscounted costs, including propulsion plant disposal".[209]

159. The MoD's memorandum of 19 February 2007 describes the process by which submarines are decommissioned. It states that

under current arrangements, when nuclear powered submarines are withdrawn from service they are defuelled as soon as is practicable and stored afloat. A longer term solution to submarine dismantling and disposal with interim storage on land of the arising intermediate level radioactive waste is being sought. If the Vanguard-class submarines were to be withdrawn from service now, the main difficulty would be provision of suitable lay-up berths until they could enter the proposed submarine dismantling facility.[210]

160. The MoD states that it is not possible to provide precise estimates of the costs of decommissioning the Vanguard-class submarine. However, it says that £827 million is included in the MoD annual accounts for the decommissioning of nuclear-powered submarines. Whether or not the UK decides to replace the Vanguard-class submarine with a new SSBN, the costs of decommissioning the Vanguard-class will still be incurred. This must be taken into account when considering the costs of retaining and renewing the nuclear deterrent. Equally, procurement of a new SSBN will, in time, mean that the MoD will incur ongoing decommissioning costs associated with the deterrent.


161. The White Paper states that the Government has "decided to participate in the Trident D5 life extension programme, at a cost of some £250 million". It says that this "is very significantly less than it would cost to acquire an alternative delivery system".[211] It also states that the Government "will continue to participate in the joint UK/US support arrangements for the D5 missile at the facilities at King's Bay, Georgia" which, it says, "represents excellent value for money".[212]

162. The Government says that the cost of UK participation in US plans to extend the life of the Trident D5 missile will be around £250 million. We call upon the Government to state whether any further expenditure will be needed to acquire the life-extended missiles over and above the initial buy-in costs to the life extension programme.

Industrial aspects

163. The White Paper considers the industrial aspects of the decision to procure a new generation of ballistic missile submarines. It argues that "designing and building new SSBNs, and integrating them with other elements of the overall system, will be a significant technical challenge for the Ministry of Defence and industry." It states that the construction of these boats "represents in engineering terms, one of the most complex and technically demanding systems in existence" which requires a "specialist subset of skills within the maritime industry".[213]

164. The Government argues that "lessons have been learned" from the delays and cost overruns experiences in the Astute-class SSN programme. But it accepts that "more change is needed for industry to be able to deliver a new programme on time and at an acceptable cost".[214] The White Paper states that "it would be our intention to build the new SSBNs in the UK". This would be "for reasons of nation sovereignty, nuclear regulation, operational effectiveness and safety, and maintenance of key skills". But it argues that "this is dependent on proposals from industry that provide the right capability at the right time and offer value for money". It maintains that "progress towards industrial consolidation and a sustainable industrial base will be an important ingredient" and states that "final decisions will be taken in the lead up to the placing of a contract for the detailed design of the submarines".[215]

165. The White Paper anticipates "a much greater collaborative effort between the MoD and industry than has been the case in the recent past".[216] And it says that "a key to successful procurement in the UK would be to work closely with industry right down the supply chain to put in place sustainable collaborative arrangements that run through the life of the platform". According to the White Paper, "this is important for driving down the whole life costs of the programme".[217]

166. Our second report on the future of the UK's strategic nuclear deterrent examined the manufacturing and skills base issues that would need to be considered in any decision to renew the submarine-based deterrent. We noted that building and maintaining a new generation of nuclear submarine would require a uniquely skilled and specialist workforce, and a dedicated manufacturing and support infrastructure. And we recognised the difficulties involved in sustaining them and that continuity of work was needed in order to sustain the UK's capability to design, manufacture and maintain nuclear-powered submarines.[218]

167. We argued that affordability had to be a fundamental consideration in any new submarine programme. And we stated that if the Government decided to procure a successor to the Vanguard-class boat, industry had to collaborate more effectively to drive down costs throughout the supply chain. We said that the MoD had to provide industry with clarity and consistency about the operational requirements and specification for a new submarine and that it was essential that lessons had been learned from the Astute-class programme. We noted that the MoD had to develop the capacity to manage a programme of the likely scale of a Vanguard successor and that any shortfalls in its preparedness had to be addressed as a matter of priority.

168. In its response to our report, the MoD states that "promoting greater industrial collaboration is a key priority for the MoD". And it says that it is "looking to industry to deliver an indigenous industrial base that is affordable for the procurement of submarines and which sustains crucial capabilities". It recognises that "proper attention should be given to through-life costs at the initial design stage for the new submarines" and states that "the bringing together of the Department's submarine acquisition and support teams from across the Defence Procurement Agency (DPA) and the Defence Logistics Organisation (DLO) under the Director General Nuclear in April 2006 has created a clearer focus on through-life support and costs". The MoD also suggests that it has "learned a number of lessons from experience with the Astute programme" and it says that it "intends to agree prices for any future submarine orders at an earlier stage than has been possible on Astute hulls 2 and 3".[219] The MoD also states that it is "clear that to execute a programme of this size and complexity it is essential that the necessary skills are available in-house and in industry". Accordingly, the MoD says that it has "embarked on a major programme of work to address skills requirements and shortages".[220]

169. The Government states that greater industrial collaboration and affordability are essential components in any new submarine programme and that it needs to address its own shortage of skills in managing a programme of the scale of a Vanguard successor. The MoD must ensure it has the skills necessary to delivery any future submarine programme to time and on budget. In the event of Parliament voting in support of the renewal of Trident, industry and the MoD must work together to drive down and control costs in order to deliver an affordable submarine programme.

Future decisions

Three or four submarines?

170. The White Paper refers to the possibility of reducing the number of ballistic missile submarines from four boats to three. It states that

We are not yet in a position to make a firm judgement about how many submarines we require in future because we do not yet understand comprehensively the likely operational availability of the replacement SSBNs. We will investigate fully whether there is scope to make sufficiently radical changes to the design of the new SSBNs, and their operating, manning, training and support arrangements, to enable us to maintain continuous deterrent patrols with a fleet of only three submarines. A final decision on the number of submarines that will be procured will be made when we know more about their detailed design.[221]

171. RUSI witnesses suggest that this is "the critical question to address" as far as deterrent options are concerned.[222] Although they accept that operating continuous-at-sea deterrence with three boats may prove to be feasible, and that technological developments "may help improve submarine availability," they warn that "a reduction to three submarines may not deliver proportionate cost savings while increasing the level of risk". Four boats, by contrast, "provide sufficient redundancy in the system for something as critical as the national nuclear deterrent, should something unforeseen occur to one of the submarines".[223] RUSI witnesses also note that a decision to reduce the flotilla to three boats would also impact upon the UK's requirement for SSNs to protect the deterrent, which "may increase arguments to reduce the number of SSNs further".[224]

172. Dr Jeremy Stocker, meanwhile, accepts that relying on three, rather than four, boats to provide continuous-at-sea deterrence "would generate a modest cost-saving and also provide a further disarmament gesture". However, he argues that "there must be some operational risk and a danger of undermining the whole credibility of the deterrent by repeated pruning at the margins".[225]


173. As noted above, the White Paper maintains that the design and manufacture of a new SSBN is likely to take around 17 years. It states that the Government has now "started to consider some of the fundamental design issues" for a replacement SSBN and has concluded that the new boat, like the Vanguard-class, will need to be nuclear-powered. It also states that "we envisage that the design of the new SSBN will maximise the degree of commonality with other in-service submarines where this can be done in a cost-effective manner". However, it notes that "some changes to the Vanguard-class will be required" .[226]

174. Dr Stocker suggests, there would appear to be three broad design options for a Vanguard successor: "an updated Vanguard; a "stretched" Astute; or a wholly new design". But he argues that "the White Paper is a little vague on this". According to Dr Stocker, an updated Vanguard "would clearly not take that period of time". While maximising commonality of design with the Astute-class would be possible, Dr Stocker argues that "the Astute-class has the same PWR-2 reactor as the Vanguard which was designed in the late 1970s and early 1980s" and that "building another class with the same propulsion system would mean having a 1980s reactor design still in service in the 2050s".

175. It is probable that a new generation of SSBNs could be designed to deliver a higher level of reliability and availability, and it is possible that this could allow continuous at sea deterrence to be ensured with only three boats. But it is also possible that the cost-savings would be small, and outweighed by the increased risk. The Government should clarify when a decision will need to be made on the number of boats in the new SSBN fleet, and what is the likely level of savings from doing without a fourth boat.


176. The Government says that the Trident D5 life extension programme, in which it has decided to participate, will ensure that the Trident D5 missile is maintained in service until the early 2040s. Beyond this date, it says a new missile is likely to be required.

177. The White Paper states that the costs of a D5 replacement would be incurred from the "from the 2030s". Whilst it suggests that "any estimate of cost would be highly speculative," it states that the equivalent cost for the Trident D5 missile was some £1.5 billion at today's prices".[227]

178. The White Paper states that the Government has received assurances from the United States that "in the event that they decide to develop a successor to the Trident D5 missile, the UK will have the option of participating in such a programme". It says that it has "also received assurance that any successor to the D5 should be compatible, or can be made compatible, with the launch system to be installed in our new SSBNs".[228]

179. The Government states that it is not yet possible to judge the potential costs of procuring a successor to the Trident D5 missile. Given that the Government intends to spend some £11-14 billion on new ballistic missile submarines, it is essential that any successor missile is fully compatible with the UK's future SSBN.

180. We note the exchange of letters between the Prime Minister and the US President, dated 7 December 2006—printed in Annex 2 to this report—to effect collaboration in the life extension programme for the Trident D5 missile delivery system. Given this exchange of letters took place three days after the publication of the White Paper and before debate in Parliament about the replacement of submarine platforms to carry such missiles beyond the life of the current Vanguard-class submarines, we look to the Government to explain the effects, financial and otherwise, of this exchange of letters agreeing the extension of this part of the Strategic Nuclear Deterrent system.


181. The White Paper states that "the current warhead design is likely to last into the 2020s, although we do not yet have sufficient information to judge precisely how long we can retain it in-service". It says that "decisions on whether and how we may need to refurbish or replace this warhead are likely to be necessary in the next Parliament". It states that the Government "will undertake a detailed review of the existing warhead stockpile and analyse the range of replacement options that might be available". It suggests that "this will include a number of activities to be undertaken with the United States under the 1958 UK-US Agreement for Cooperation on the Uses of Atomic Energy for Mutual Defence Purposes".[229]

182. The Government says that decisions on a new warhead will be required in the next Parliament. We call upon the Government to state whether the cooperation it envisages with the United States will include participation in the US Reliable Replacement Warhead Programme and why the UK could not re-manufacture warheads to the existing design.


183. On the basis of the statements in the White Paper and the evidence we received, below we suggest our understanding of the likely timeframe for future decisions.

Table 9: Suggested timeline for future decisions
Date  Decision 
2007 Decision in principle to preview new SSBNs and extend life of D5 missile  
2007-2009 Initial concept and design work for a new submarine  
c 2009-13 ("next Parliament")  Decision on replacement of warhead  
2009-2016 Detailed design work on new submarine  
2012-14 Contract to be placed for detailed design of new submarine  
2016 Contract to be placed for build of first new SSBN  
2016-2023 Build programme for first new SSBN  
2022 HMS Vanguard out of service (with 5 year life extension)  
2024 HMS Victorious out of service (with 5 year life extension)  
2024 First new SSBN in service  
2026 HMS Vigilant out of service (with 5 year life extension)

Second new SSBN in service  

2029 HMS Vengeance out of service (with 5 year life extension)

Third new SSBN in service  

2020s Decision on Trident D5 missile successor  
2030-32 Fourth new SSBN (if required) in service  
2030s Development of new ballistic missile  
early 2040s Life-extended D5 missile out of service  
2050s New SSBNs out of service  

184. It would be helpful if the Government could confirm whether the timetable we suggest is accurate or in what respects it is wrong.

185. If the White Paper's proposals to retain and renew the UK's strategic nuclear deterrent are endorsed, it is essential that the Government keep Parliament informed of the progress of the submarine, missile and warhead programmes. We expect Parliament to be consulted at each significant stage of the programmes before major procurement decisions are made.


186. The Government deserves to be commended for exposing its proposal to renew the strategic nuclear deterrent to public debate and decision in Parliament, which previous Governments have not done. We look to the Government to inform the House of Commons of any errors of fact or interpretation in this report, before the debate in March. And we hope that the Government, and the MoD in particular, will learn for the future that greater transparency is to its own, as well as to the public, advantage.

170   Cm 6994, para B.1, p 34 Back

171   Cm 6994, para B.8, p 35 Back

172   Cm 6994, para B.12, p 37 Back

173   Cm 6994, para 5.3, pp 24-25 Back

174   Cm 6994, para 5.4, p 25 Back

175   Cm 6994, para B.16, p 39 Back

176   Cm 6994, para 5.4, p 25 Back

177   Q 199 Back

178   Ibid. Back

179   Ev 114 Back

180   Ev 126 Back

181   Ev 182 Back

182   Ev 110 Back

183   Ev 122 Back

184   Ev 183 Back

185   Ibid. Back

186   Cm 6994, para B.14, p.38 Back

187   Q 357  Back

188   Cm 6994, para 5.14, p 27 Back

189   Ibid. Back

190   Cm 6994, para 1.4, p 10 Back

191   Q 323 Back

192   Q 325 Back

193   Cm 6994, para 5.11, p 26 Back

194   Ibid. Back

195   Cm 3999, para 74, p 20 Back

196   Ev 110 Back

197   Q 331 Back

198   Q 332 Back

199   Ibid. Back

200   Cm 6994, para 5.15, p 27 Back

201   Q 329 Back

202   Cm 6994, para 5.14, p 27 Back

203   Ev 116 Back

204   Cm 3999, para 74, p 20 Back

205   Ibid. Back

206   Ev 206 Back

207   Ev 205 Back

208   HC (2006-07) 304, para 18, p 8 Back

209   Ibid. Back

210   Ev 205 Back

211   Cm 6994, para 5.10, p 26 Back

212   Ibid. Back

213   Cm 6994, para 6.1, p 28 Back

214   Cm 6994, para 6.2, p 29 Back

215   Cm 6994, para 6.3, p 29 Back

216   Cm 6994, para 6.4, p 29 Back

217   Cm 6994, para 6.5, p 29 Back

218   HC (2006-07) 59 Back

219   HC (2006-07) 304, para 19, p 8 Back

220   HC (2006-07)304, para 24, p 10 Back

221   Cm 6994, para 5.0, p 26 Back

222   Ev 113 Back

223   Ev 114 Back

224   Ibid. Back

225   Ev 111 Back

226   Cm 6994, para 5.6, p 25 Back

227   Cm 6994, para 5.11, p 26 Back

228   Cm 6994, para 7.6, p 31 Back

229   Cm 6994, para 7.4, pp 30-31 Back


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