The United Kingdom's Future Nuclear Deterrent Capability - Public Accounts Committee Contents

1  Making important decisions

1. The United Kingdom's ability to maintain continuous at sea deterrence is dependent on the seamless transition from the current Vanguard fleet to the future class of submarines. By 2024, two of the four Vanguard class submarines will have gone out of service and the first of the future submarines will need to be in service. The current critical path for the future deterrent programme is therefore delivery of the submarine platform in time to meet this deadline, although this plan also assumes the successful delivery of a five-year life-extension programme for the Vanguard class submarines.[3] Key timelines for the principal elements of the future deterrent are shown in Figure 1.

2. The Department has a long history of delivering major defence projects late. The Department's unrealistic assessment of project delivery timetables has often meant that major projects also frequently exceed their budgets. The current Astute submarine programme provides a good example of this, since it is already over three years late against its planned in-service date and around £1.3 billion over budget. This increase in expenditure constitutes a 47.3% cost overrun.[4]

3. The Astute submarine procurement programme has suffered from a range of problems, including slow contract negotiation, an ill-advised attitude to risk and difficulties with a computer-aided design tool. Furthermore, the length of time elapsed between the Vanguard and Astute programmes meant that key skills and submarine-building expertise disappeared. There has also been unplanned cost growth such as increases of £164 million and £68 million for materials and labour respectively.[5]

4. The Department understands that, if it is to avoid jeopardising continuous at sea deterrence, there is no room for the future deterrent programme to experience similar delays to the Astute programme. Although the current Vanguard fleet could be extended beyond the five years envisaged under the planned optimisation programme, any further extension of the current submarines is likely to add extra cost and risk.[6]

5. The Department has yet to make a number of key decisions, including finalising the principal design parameters of the submarine, the type of nuclear reactor and the design and size of the missile compartment.[7] The Department has until 2014 to decide whether to build three or four submarines.[8] At present, the Department believes that four submarines will enable the United Kingdom to maintain continuous at sea deterrence. A new design of submarine with increased reliability might allow the same level of coverage to be maintained with three submarines.[9]

Figure 1: Summary timeline for the replacement of the deterrent capability

6. The Department has yet to choose between using a variant of the existing 'PWR2' nuclear reactor and developing a new reactor—'PWR3'—but intends to do so by September 2009, its Initial Gate approval milestone.[10] Both choices present opportunities as well as costs. The PWR2 model has the benefit of being based on existing technology, but will require updating because of the risk of obsolescence.[11] The PWR3 option offers the advantage of increased efficiency, but presents an added risk to the timeline as it requires a substantial amount of research and development.

7. The Department faces a difficult judgement in deciding how much options analysis work to undertake before settling on the key design features of the submarine. The Department is attempting to complete the submarine design and build process in 17 years, against the 18 year timetable which is generally accepted as necessary (including two years for concept, seven years for design, seven years for construction and two years for sea trials). The Department intends to manage this timetable misalignment by overlapping the design and construction phases. This approach will mean that construction will commence before the completion of submarine design.[12]

3   C&AG's Report, para 1.8 Back

4   Qq 18-19 Back

5   C&AG's Report, Box 3 Back

6   Q 4 Back

7   C&AG's Report, para 2.8 Back

8   Q 63 Back

9   Q 46 Back

10   Q 76 Back

11   C&AG's Report, para 1.14 Back

12   Qq 59-60 Back

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Prepared 19 March 2009