Written question asked by Mike Hancock (Liberal Democrat) on Monday, 13 July 2009, in the House of Commons. It was due for an answer on Wednesday, 15 July 2009. It was answered by Bob Ainsworth (Labour) on Tuesday, 1 September 2009 on behalf of the Ministry of Defence.

Trident

Question: To ask the Secretary of State for Defence how much has been spent on Trident II; and what his Department's estimate is of how much it would cost to order (a) three and (b) four boats to replace Trident I.

Answer: The current Trident II D5 missile is expected to remain in service until 2042. No expenditure has been incurred on a successor to the Trident II D5 missile.As set out in the 2006 White Paper, we estimate that the procurement costs of the replacement for the current Vanguard class submarines will be between £11-14 billion at 2006-07 prices. The total spent on the replacement submarine and associated propulsion system since the beginning of April 2007 to the end of June 2009 is some £250 million.Work is ongoing to assess whether continuous at sea deterrence could be achieved with a three boat fleet, and at what cost.

Secondary information