UK plan for Trident replacement takes shape

The UK's next-generation ballistic-missile submarines will have 12 missile tubes rather than the 16 aboard the existing Vanguard-class Trident-armed submarines, British Prime Minister Gordon Brown said on 17 March.

"Our latest assessment is that we can meet this requirement with 12 - not 16 - missile tubes, as are on current submarines," Brown told the International Nuclear Fuel Cycle Conference in London.

The earlier Resolution-class Polaris submarines were armed with 16 tubes, the same number as are installed on US Polaris and Poseidon armed submarines, while the US Navy's current Ohio-class Trident submarines have 24 launch tubes.

Brown also confirmed that the UK's stockpile of operationally available nuclear warheads now numbered "fewer than 160. If it is possible to reduce the number of UK warheads further, consistent with our national deterrence and with the progress of multilateral discussions, Britain will be ready to do so". he added.

Meanwhile, a report from the UK House of Commons Public Accounts Committee published on 19 March described some of the problems that the UK will face in developing the new submarines.

By 2024, two of the four current Vanguard-class submarines will have gone out of service and the first of the future submarines will need to be in service. As currently planned, the design and build process for the new class is expected to take 17 years, rather than the 18 years generally accepted as necessary for such a project. This will require a year-long overlap between the design and construction phases, with construction starting before the design is complete.

This plan assumes the proposed five-year life-extension programme for the Vanguard-class submarines will be successful. An extension beyond five years might be possible, Permanent Under Secretary of State Sir Bill Jeffrey told the committee. "Any further extension would inevitably involve extra cost and risk," he said. "The thing about these very complex nuclear submarines is that the longer you keep them in service the more out-of-service they need to be for purposes of maintenance etc.