I refer the hon. Member to the statement I made on 25 July 2007, Official Report, column 871, in which I confirmed that the new aircraft carriers are to be base-ported in Portsmouth.
Several types of vessels will provide escort and security for the aircraft carriers, and the numbers employed will vary according to the threat faced. There are many variables involved in determining the number of ships required to defend a carrier or amphibious task group. These include the level of the threat, the level of multinational involvement and the type and scale of the operation. We currently have a contract for six type 45 destroyers.
The project to provide two future aircraft carriers is currently expected to cost £3.9 billion. There is agreement and a scheme of incentives, however, to work with industry to reduce this before a final price is settled by 2010.
In-service dates are not set until Main Gate, when the project is mature enough for us to take a view on the appropriate date. That point was reached in July and the dates (2014 and 2016) have been set.