A LAST-MINUTE offer which would increase fire fighters' pay to more than £25,000 will be put to union leaders this morning in a desperate attempt to avert an eight-day strike.

Local authority employers were last night working on a surprise 11th hour pay deal which would increase salaries from the present £21,500 to £25,000 outside London and £28,000 in the capital by this time next year.

The possible breakthrough comes amid mounting pressure to settle the dispute before the first eight-day stoppage begins at 9am tomorrow, following last week's 48-hour strike.

With Army-manned Green Goddesses poised to return to the streets, the head of Britain's armed forces warned yesterday that the use of servicemen during the fire strike was putting a severe strain on the military ahead of a probable war with Iraq - to the acute embarrassment of the Government.

Details of new pay package - which will be conditional on the unions accepting modernisation measures - emerged from the employers' negotiating body last night.

No official comment was made but sources said an "absolutely exceptional deal" was being drawn up.

It is understood that the initial payment would remain at four per cent but there would be staged rises over the next year, each one linked to modernisation.

The union is calling for a 40 per cent pay rise and has already rejected an offer worth 11.3 per cent over two years. But, crucially, union officials have already indicated that a 16 per cent offer - roughly the equivalent of the offer being tabled this morning -- would settle the dispute.

"Hopefully they will call off the strike, accept this is a fair offer and we can get down to talking," said the source.

Local authority employers and Fire Brigades Union leaders held separate meetings yesterday.

FBU general secretary Andy Gilchrist, speaking before details of last night's improved offer emerged, said: "We have always been prepared to look at a serious and significant offer on pay. We have not had one.

"Because we do need to resolve this, we have indicated we are prepared to meet employers tomorrow to see what they have got to offer us."

The stakes were raised for the Government yesterday when Defence Secretary Geoff Hoon was left visibly squirming as Chief of Defence Staff Admiral Sir Michael Boyce admitted he was "extremely concerned" that the need to have thousands of servicemen on standby to cover for the firefighters was affecting training and morale.

"We don't have a box of 19,000 people to be called upon to do firefighting duties. They must have been from operational units," he said.

"Clearly we cannot perform to the full extent of our operating capability while we have 19,000 people standing by to do firefighting duties."

Mr Hoon, standing alongside him at the briefing in Westminster, said: "What we have to do always is maintain an appropriate level of response to the tasks that ultimately the Government ask of the armed forces.

"It is my job clearly, on the advice that I am given by the Chiefs of Staff, to make sure that we are able to respond to any emergency in any situation and that remains the position."

Admiral Boyce's warning could hardly have come at a more awkward time for the Government as Mr Hoon disclosed that the US had now lodged a formal request for military assistance in the event of an attack on Iraq.

In the Commons later, Tony Blair said the US request was at this stage simply a general inquiry and that they had not been asked for specific forces.

He said that about 60 other nations had been sounded out in the same way by Washington.

"We have received the same general request as everyone else," said Mr Blair. "We haven't received a specific request in relation to specific troop requirements," he told MPs at Prime Minister's Questions.

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