Three-minute nuclear warning is now three days

It used to be known as the three-minute warning - now it's the three-day warning. That is the notice period Britain's nuclear deterrent needs before it can be fired.

The Royal Navy is so short of cash, it is claimed, that its nuclear submarines are too busy making maps and testing equipment to monitor potential enemies full time.

However, the Ministry of Defence say there is nothing to fear. Military analysts are confident that there would be a recognisable build-up to any nuclear conflict in the future, which would provide the UK ample time to target its nuclear deterrent.

MoD sources also point out that every country is vulnerable to arbitrary attacks, which is precisely why the United States is considering building an antiballistic missile shield, which could eventually cover the UK. Also, as a member of Nato, the US is committed to defending the UK.

However, Mike Hancock, Lib Dem MP for Portsmouth South and a member of the defence select committee, believes that the change in the notice-to-fire period displays a much more worrying trend. He has accused ministers of downgrading Britain's nuclear subs by stealth because the Navy is overstretched.

This decline in Britain's state of nuclear readiness is the latest in a series of embarrassing cost-cutting measures forced on the Armed Services.

Late last year, the Independent on Sunday reported that the Fleet had been confined to port in order to conserve fuel. Then it emerged that RAF planes had been grounded due to a shortage of spare parts.

Mr Hancock said: "I believe the Navy is being forced to 'down gun' Trident to do jobs normally carried out by hunter- killer submarines."

The extended response time is not widely known but was buried away in Labour's Strategic Defence Review and has already been operating for 20 months.

Geoff Hoon, the Defence Secretary, admitted in a parliamentary answer that there was a decision "to maintain our nuclear forces at a notice-to-fire [period] measured in days, rather than minutes.

"This reduced state of alert allows greater use of ballistic- missile submarines for secondary tasks," he explained.

A Ministry of Defence spokesman last night said that nuclear subs were being used on equipment trials, hydrographic surveying and exercises with other vessels.

Mr Hancock, whose Portsmouth South constituency contains the Navy's biggest base, believes the Admiralty is being faced with some impossible choices.

According to Mr Hancock, Labour's decision to buy two new aircraft carriers is causing concern throughout the MoD because "nobody knows what is going to have to go in order to pay for them".

Mr Hancock said: "If Trident nuclear submarines are being used now for mundane tasks, what is going to happen when the Navy's two aircraft carriers come in line in a decade's time? Will Trident submarines be guarding them instead of conventional nuclear-powered submarines?

"Politically, they can't get rid of the nuclear deterrent, so the obvious solution is to get rid of the hunter-killer submarines. We seem to be heading towards a farcical situation where hugely expensive submarines are being used for inappropriate missions."

An MoD spokesman said that the Navy had ordered new Type 45 destroyers, Astute Class submarines and new aircraft for the two aircraft-carriers, all due to be delivered early in the next decade. "We are delivering the equipment the Navy needs. It is up to it how to deploy the vessels."