Question to the Ministry of Defence:

To ask the Secretary of State for Defence, pursuant to the Answer of 30 November 2015 to Question 17622, if he will identify separately the marginal costs associated with maintaining the Vanguard submarines in service for five years longer then envisaged.

As announced in Strategic Defence and Security Review (SDSR) 2010 we can extend the life of the existing Vanguard class submarines into the early 2030s. Cost estimates for supporting the ballistic missile submarines during the transition from Vanguard to Successor are not materially affected by minor changes to scheduled dates.