The Royal Navy operates four Vanguard-class ballistic missile submarines equipped with the Trident nuclear missile. The coalition government is internally divided over the decision to order replacement submarines to come online when the current subs reach their designed end-of-life. The Tories (at least for public consumption) are in favour of a replacement on a one-for-one basis, while the Liberal Democrats would prefer to eliminate nuclear missiles from the British arsenal.
In the Telegraph, Peter Dominiczak explains why the one-for-one replacement is the least likely outcome:
Mr Alexander, the Chief secretary to the Treasury, dismissed Tory demands for a new continuous at-sea nuclear deterrent and warned that the Treasury does not have “a magic pot of money” to pay for a new generation of submarines.
In an interview with the Guardian he insisted that there are “potential alternatives” to Trident.
The Liberal Democrats have repeatedly clashed with Conservatives who are calling for an upgrade to the fleet of Trident submarines.
The Lib Dems insisted on an official review into Trident, which is due to report in June, as part of the Coalition agreement in 2010.
[. . .]
“Is it right in the 21st century that we still need to have submarines at sea, 24 hours a day, seven days a week, 12 months of the year? All those things are ripe for being reviewed and considered, and alternatives presented.”
Philip Hammond, the Defence Secretary, last year said that upgrading Trident would probably be cheaper than any alternative nuclear deterrent proposed by the Lib Dems.
He said the Trident missiles and warheads have “many, many years of life in them” and will only need new submarines to carry them by 2028.
Any attempt to create a whole new nuclear deterrent system is unlikely to be economic, he said.
Ballistic missile submarines are very expensive to design and build (and to operate), and shifting to a smaller number of hulls would save very little money. As I put it back in 2010, “Army, RN, RAF, and Trident replacement: pick any three“. Trident is nearly as expensive as an entire arm of the military all on its own, and it’s no surprise that the Liberal Democrats would love to eliminate it if they could get away with it.