Current departmental plans expect that construction of the successor to Vanguard class submarines will occur in parallel with construction of later Astute Class Submarines. The lessons learnt from the Astute programme are being applied to the design and build phase of the successor programme. Any opportunities arising from the successor programme that may benefit the Astute Class will be considered as part of normal business between closely related programmes.
The Trident II D5 ballistic missile is the delivery system for the UK’s nuclear deterrent that is carried by our Vanguard-class submarines. It is an evolutionary development of the Trident IC4 missile that the UK originally planned to procure but was superseded by a decision in 1982 to procure the Trident II D5 missile. As we made clear in the December 2006 White Paper: “The Future of the United Kingdom’s Nuclear Deterrent” (Cm 6994), we are participating in a programme to extend the life of the Trident II D5 missile until around 2042.
With regard to the new class of submarines to replace the Vanguard-class, as we have previously stated, the first of class is forecast to enter service in around 2024. Also, as explained in the December 2006 White Paper, a final decision on the number of submarines that will be procured will be made when we know more about their detailed design. That decision will determine the timetable for entry into service of further submarines.