Question to the Ministry of Defence:

To ask the Secretary of State for Defence, what recent estimate he has made of the capital costs of (a) replacing the Vanguard fleet with four new Successor submarines and (b) other foreseeable elements within the Trident renewal project up to the late 2030's.

As stated in the Strategic Defence and Security Review 2015, our latest estimate is that manufacturing the four Successor submarines is likely to cost a total of £31 billion, including inflation over the lifetime of the programme. We will also set a contingency of £10 billion. The MOD budget for the Spending Review period published in Budget 2016 included this latest estimate for the relevant period.