Britain’s nuclear-submarine fleet may shrink

SOMEWHERE deep at sea, a 150-metre submarine potters around with a cargo of 16 nuclear missiles. Britain has four such submarines, though only one is usually armed while the other three undergo repairs or whirr around on training manoeuvres. On September 23rd Gordon Brown, the prime minister, announced that the fleet of four could be cut to three.

The statement came just before a meeting of the UN Security Council on bolstering the world’s non-proliferation regime, at which Mr Brown was due to present the move as a gesture towards disarmament (there is no word on whether he plans to reduce Britain’s 160 warheads too). It is also a time when the government is desperate to save money, not least on the stretched defence budget. Trident, as Britain’s nuclear programme is known, has been proposed for the chop, mainly by those on the left, for decades. The decibels peaked in 2007 when Parliament voted to renew the ageing submarines.

Reducing the size of the fleet by a quarter will not cut the bill by the same proportion. Much of the estimated £20 billion ($33 billion) cost of renewing Trident will go on fixed overheads; building four submarines is not that much more expensive than three. (Even getting rid of the Trident programme entirely would not save anything like the full whack for running it because of the costs involved in clean-up.)

In fact, the announcement probably has less to do with cost-cutting than with Britain’s longstanding interest in nuclear disarmament. The idea of having just three submarines has been around for a while, prompted by hopes that the new vessels might need less repair and refitting than the old ones. Successive prime ministers have made clear their willingness to cut Britain’s nuclear capabilities to the bone in the context of multilateral disarmament. (France, the other European nuclear power, has been more reticent.) Having reduced its warheads over the years, Britain now has the fewest of the five officially recognised nuclear powers.

The remaining question is how far removing one of the four subs would affect Britain’s defence capabilities. If the new models are reliable, there should be no problem hanging on to the permanent at-sea presence that defence bosses favour. If not, the ships might have to be sent out only at times of tension—bad for security, not to mention for diplomacy.