To ask the Secretary of State for Defence what the (a) unit cost and (b) date of commissioning of each Upholder Class submarine was. (218232)

The upholder class of four submarines was commissioned in the early 1990s and the exact dates are shown in the following table. This class was sold to the Canadian Navy in 1998.

Due to the length of time that has elapsed since their commissioning, the unit cost is no longer held centrally and could be provided only at disproportionate cost.