Select Committee on Defence Written Evidence

Annex A

1.   A note estimating the decommissioning costs of the Vanguard-class SSBNs in the event that a decision was taken to abandon the nuclear deterrent now [Q 337].

  It is not possible to provide a precise estimate of the costs that would be incurred in decommissioning the four Vanguard-class submarines in the hypothetical circumstances that a decision was taken to abandon the nuclear deterrent now. In the Government's response to the Committee's report on The Future of the UK's Strategic Nuclear Deterrent: the Manufacturing and Skills Base we explained that the MoD's strategy for de-commissioning nuclear-powered submarines is currently under review in the light of revised project proposals for de-fuelling facilities and the 2006 report of the Committee on Radioactive Waste Management.

  Under current arrangements, when nuclear powered submarines are withdrawn from service they are defuelled as soon as is practicable and stored afloat.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 If the Vanguard-class submarines were to be withdrawn from service now, the main difficulty would be provision of suitable lay-up berths until they could enter the proposed submarine dismantling facility.

  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 out 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 (HC1394). £837 million is included for the decommissioning of submarines, up to and including Vanguard-class.

2.   A note outlining how the support costs of £600 million per annum are divided between SSBNs and SSNs, and estimating how much would be saved if the SSBNs were no longer operated [Q 339-340].

  We estimate that the current cost of supporting the SSBN and SSN fleets averages around £600 million a year. This figure covers the costs of maintaining the submarines themselves, including for replacement parts and systems, equipment and the operating costs of the naval bases that provide support. It does not include costs associated with supporting the strategic weapons system (ie the missiles and their launch systems and the warheads) installed on the SSBNs.

  On average the £600 million is divided more or less evenly between the SSBN and SSN fleets, but there is some variation from year to year reflecting peaks and troughs in major maintenance periods. A substantial proportion of these submarine support costs (around 80%) are considered to be fixed, that is they are not directly activity dependent. Ending SSBN operations could therefore be expected to generate only relatively modest savings in submarine support costs, of less than £100 million a year.

3.   The estimated in-service costs of the UK's nuclear deterrent, expressed in monetary terms instead of percentage of the defence budget [Q345].

  We have previously said 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. That estimate was based on the planned near cash defence budget of £28,700 million in 2006-07. We estimated that actual expenditure would be around £1,500 million.

4.   A note outlining when each of the existing Vanguard-class SSBNs are due to leave service, when each of the new generation of SSBNs will enter service, when a decision is required on whether to procure a fourth boat in the fleet of successor SSBNs, and how the MoD will evaluate whether it can operate continuous-at-sea deterrence with three rather than four SSBNs [Q 383].

  The dates when the four Vanguard class submarines are due to leave service, with or without a life-extension programme, were set out in the attachment to the letter from the MoD Liaison Officer to the Clerk of the Defence Committee, dated 1 February 2007.

  We plan that the first of the new submarines will enter service around the time that HMS Victorious leaves service (ie around 2024) and that subsequent new boats will enter service as each Vanguard-boat is withdrawn. However, the precise management of the transition between the two classes of submarines will depend on a range of factors, including the number of new boats to be procured, and the availability of the Vanguard-class submarines as they reach the end of their lives.

  As the White Paper makes clear, we will not be in a position to make a final decision on the number of hulls to be procured until we have a clearer idea of the design of the new submarines and their likely operational availability. A final decision on this is not essential for some years, but it may prove to be cost effective to take this decision earlier than is absolutely essential in order to inform and help focus subsequent detailed design work.

  A key part of the forthcoming concept and assessment phase will be to determine the key design parameters of the new submarines. We will also need to review the operating, manning, training and support arrangements. This in turn will enable us to judge the likely availability of the new submarines and hence the risks associated with seeking to maintain continuous at sea deterrence with a fleet of three submarines. We will also assess the potential financial savings from this approach. This will enable a final judgement to be taken on the cost-effectiveness of a three versus a four boat solution.

19 February 2007

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