John Edmonds, general secretary of the GMB, called on the trade union movement to stand shoulder to shoulder with the Fire Brigades Union (FBU).

He also condemned government demands that the firefighters follow TUC guidelines and provide emergency cover during the strike.

The fire service minister Nick Raynsford has challenged the FBU's general secretary about the guidelines, and Deputy Prime Minister John Prescott will make a statement to the House of Commons on Tuesday afternoon.

'Blackmail'

But Derek Simpson, joint general secretary of Amicus, said the guidelines were a "red herring".

"It is nothing more than a smoke-screen to cover-up the government's unwillingness to negotiate with firefighters over their claim for a living wage," he said.

For the duration of an industrial dispute, the union(s) involved should, where necessary make arrangements in advance and with due notice, in consultation and preferably by agreement with the employer, for the maintenance by their members of supplies and services essential to the health or safety of the community

TUC code of conduct

And Andy Gilchrist, FBU general secretary, accused the government of "blackmailing" his union into calling off the strikes.

Mr Gilchrist said the FBU had been "absolutely open and honest" with the public over the dispute for "months".

"It's only yesterday that the government phone up and finally admit to us that their alternative arrangements are frankly wholly inadequate, and in some way wish to blackmail us into assisting them," he said.

The TUC's guidelines were drawn up after the Winter of Discontent in 1979 when public services were seriously hampered by widespread strikes.

In them, the TUC agrees pledges to maintain services vital to the safety of the community.

The government brought them up at a meeting on Monday and it has emerged that the TUC General Secretary John Monks has also raised the issue.

Green Goddesses

All unions have adhered to the code in recent years.

During the nationwide ambulance dispute over pay in 1988, workers covered genuine emergencies of "life and limb", refusing only to do routine ferrying of patients around.

"Although we already have national contingency plans in place, clearly the risk to the public would be reduced if we had clarity about the likely response of FBU members in the event of life-threatening incidents," said Mr Raynsford.

Strike dates

29- 31 October 2-4 November 6 November -14 November 22-30 November 4-12 December 16-24 December All start and end at 0900 GMT

The government also plans to explain why the Army, which will step in during the strike, is still using ancient and slow Green Goddesses.

A spokesman said it was not because the government did not want soldiers to cross picket lines but rather the impracticalities of taking modern red engines out of service for Army training.

The industrial action is being supported by 11 Labour MPs who signed a Commons motion backing the firefighters.

One of them, Jeremy Corbyn, said: "Maybe this is an opportunity for the prime minister to intervene, or ensure a senior minister intervenes and has face-to-face discussions with the firefighters."

Meanwhile a number of part-time firefighters in Scotland have joined the FBU so they can take part in the strike.

The retained firefighters at four stations in the north-east will join their full-time colleagues on the picket lines.

Cost of strike

Firefighters are demanding a 40% pay rise, which would see salaries for fully qualified staff rise to about �30,000.

Chancellor Gordon Brown warned on Tuesday he would not provide any extra cash to settle public sector pay claims like the firefighters' demands.

Sir Jeremy Beecham, chairman of the Local Government Association, said the employers were standing by their offer of a 4% increase and a review of working conditions.

The FBU predicts the strike will cost over �5.2m per day, based on the cost of a strike in Merseyside last year.

Full-time firefighters are planning to begin the series of walkouts on 29 October. Strikes will last for up to eight days at a time, and are planned to take place over 36 days.

The Army - backed by the Royal Navy and RAF - is on standby to provide cover with 827 Green Goddess fire engines.

They will be joined by 4,000 part-time firefighters with the Retained Firefighters Union (RFU), which has condemned the FBU's action.