A rift in the coalition government over the country's nuclear weapons widened on Tuesday when the defence minister called another minister's proposals to scale them back "either naive or reckless".
The ruling Conservative party and its junior coalition partner, the Lib Dems, have long disagreed over the issue, but a new government review of Britain's multi-billion pound submarine-based Trident nuclear missile system has reopened the dispute.
With a parliamentary election looming in 2015 and a decision due soon after that on how to replace the ageing deterrent, the two parties' positions on such an important issue could influence the make-up of any future coalition government.
The results of the review will be released later on Tuesday, but the Liberal Democrat minister in charge of the exercise, Danny Alexander, is expected to say that the number of submarines operated could be cut from four to two.
Alexander conducted the review to see if a cheaper option could replace the system at a time when Britain is mired in debts. The Conservatives want a like-for-like replacement.
On Tuesday, they said reducing the number of submarines by one or two would end Britain's ability to have a continuous sea-borne deterrent by having a submarine at sea 365 days a year.
"I think it's frankly either naive or reckless," Defence Minister Philip Hammond, a Conservative, said of the proposals. "We do not believe that, with nuclear threats if anything proliferating, with more countries seeking to get nuclear weapons, this is the time to downgrade," he told BBC radio.
Trident missiles are built by Lockheed Martin Space Systems and are also used by the U.S. navy. The submarines are operated from Scotland, which is holding an independence referendum next year. Scots nationalists oppose their deployment.