To ask the Secretary of State for Defence what the estimated cost to his Department is of extending the out-of-service date of the existing fleet of submarines until the in-service date of the Astute class submarines is reached. (169620)

The out of service dates of the Swiftsure and Trafalgar class submarines were adjusted during the Department's 2004 planning round to reflect the planned in-service dates of the Astute class submarines and the decision, announced in the July 2004 White Paper Delivering Security in a Changing World-Future Capabilities (Cmd 6269), to reduce the size of the submarine fleet. As a consequence, some submarines had their service lives extended, and others had theirs reduced. No estimate has been made of whether any associated costs are specifically attributable to adjustments to the out of service date of the existing fleet to meet the in-service dates of the Astute class.