I refer the hon. Member to the written ministerial statement I made on 25 March 2010, Official Report, columns 54-55WS. Of the seven planned Astute class submarines, the first four boats have been ordered. Boat one (Astute) is currently undergoing an extensive programme of sea trials while boats two to four (Ambush, Artful, and Audacious) are in various stages of construction. We have decided to proceed with the initial build work on boat five and to order the long lead items for boat six. The delivery timetable for the class is currently being re-baselined.
We are continuing to target an in-service date for the first Trident successor submarine of 2024, as set out in the White Paper ‘The Future of the United Kingdom's Nuclear Deterrent’ (Cm6994). The precise delivery schedule will be determined at Main Gate, currently scheduled for 2014.
The Ministry of Defence and industry are evaluating the lessons from the first boats in the Astute programme and will ensure that there is appropriate sequencing between the Astute and successor programmes to ensure that continuous at sea deterrence can be maintained. We do not expect delays in the Astute programme to affect the timetable for the delivery of the Trident successor submarines.