A new defense review by the UK government estimates the cost of building four new ballistic missile submarines to be 31 billion pounds (about $45.5 billion), an increase of 17-20 billion pounds over the last formal government estimate of 11-14 billion pounds nearly a decade ago.
The defense review also announced a new investment plan and deployment date for the new submarines.
The United Kingdom currently possesses four Vanguard-class submarines armed with Trident missiles carrying a total of 120 nuclear warheads. (The submarines sometimes are also called Tridents.) The government is planning to replace these submarines with a fleet of four new ones.
The 2015 cost estimate to build the submarines includes the effects of inflation over the 20 years it will take to acquire the boats. The review said the total cost to design the new submarine fleet would be an additional 3.9 billion pounds, a portion of which has already been spent.
The review is also setting aside a “contingency” fund of 10 billion pounds, apparently to help address potential increases in the manufacturing cost of the submarines.
The review did not include an estimate of the cost to operate the new boats over their expected lifetimes. Reuters reported last October that the cost to build and operate the fleet and its supporting infrastructure will reach 167 billion pounds, citing figures provided to Crispin Blunt, a Conservative member of Parliament, by the Ministry of Defence.
In 2011 the government approved a five-year preparatory research and design phase for the new submarines. The key set of investment decisions on the program, known as Main Gate, had been scheduled for 2016, to be followed by a vote in Parliament. But the review said the government is “moving away from a traditional single ‘Main Gate’ approach, which is not appropriate for a program of this scale and complexity, to a staged investment programme.”
The review did not detail what this new approach will look like.
It also is unclear whether and, if so, when the Conservative Party, which strongly supports the replacement of the current submarines and currently holds a majority in Parliament, will seek a vote in Parliament in favor of the replacement program.
According to the review, the first new submarine is slated to enter service in the early 2030s. Previous government statements had said the first new submarine would be in the water in 2028.