The Government was last night accused of trying to blackmail firefighters ahead of a wave of pay strikes as the heat was turned up in the increasingly bitter dispute.

Deputy Prime Minister John Prescott attacked the planned 36 days of stoppages as "completely unjustified" and condemned the Fire Brigades Union's 40 per cent pay claim as "simply indefensible".

The union hit back, accusing the Government of trying to "morally blackmail" firemen and women with calls for them to follow TUC guidelines on protecting the public during strikes.

The TUC general council said it expressed strong support for the FBU and had set up a special group to work with the union to try to settle the dispute.

The group, which includes Unison general secretary Dave Prentis and GMB leader John Edmonds, will also discuss the TUC guidelines, which were drawn up after the 1979 Winter of Discontent.

The Government has pressed the FBU to follow the guidelines and not put the public's safety at risk.

But Andy Gilchrist, general secretary of the FBU, said the Government had six days to settle the dispute before any lives were put at risk when the strikes start next Tuesday.

"They need to stop morally blackmailing professional firefighters' and start genuine talks over pay," he said.

Retained firefighters across the country are being asked by fire authorities if they plan to join industrial action on strike days.

Fire chiefs fear that such a move will only exacerbate the lack of cover in huge rural areas such as North Yorkshire.

The county's fire and rescue service expects to hear on Friday whether its 370 retained staff, who are all part-time, will join the strikes.

Many retained firefighters who hold FBU membership have already indicated their support.

Retained firefighter George Barrass, sub-officer at Stanhope fire station in County Durham, said his ten men crew, who are all members of the FBU, had voted to join the strike and were backing their full-time colleagues.

But he said that if they were faced with a life-threatening incident or disaster, they would not hesitate to turn out.

"We all live and work in this community and our greatest concern has to be the safety of the people of the dale.

"If human life is put in danger, there is no chance of us sitting back and doing nothing," he said.

Earlier, Mr Prescott had told the Commons that contingency arrangements were in place to provide emergency cover on strike days - but warned that the "risk of loss of life and property will be higher". The public was urged to take "sensible precautions" in homes and workplaces.

Mr Prescott called on the FBU to provide a "constructive" response to the Government's request for clarification of the extent to which it would continue to respond to life-threatening incidents.

Transport Secretary Alistair Darling warned that fire services would not be on hand to cut people from the wreckage of serious road accidents and that back-up by police, ambulance and armed forces was "no substitute".

The UK economy would take a £200m daily hit if the rail network was shut down as a result of the firefighters' dispute, according to accountancy group Tenon