In an emergency statement to MPs on Thursday evening, John Prescott urged the firefighters' union to cancel the stoppage, stay at the negotiating table and work out a deal.

It came after angry union leaders said they had been made a "totally unacceptable" pay offer.

Work out a deal which is fair to firefighters and fair to all

John Prescott

Talks between the Fire Brigades Union (FBU) and employers continued into the early hours of Friday.

Earlier talks had stalled after the employers made a final offer of an initial 4%, with a further 12% over the next year if the union accepted a package of modernisation.

That would take a qualified firefighter's salary to �25,000 (�28,000 in London) by November 2003.

The union, which has been demanding a 40% rise, had expected the offer of 16% to have no strings attached.

FBU general secretary Andy Gilchrist said the discussions would continue and were at a delicate stage.

If the FBU reject this offer it will be clear to all that their action is no longer driven by wanting a fair deal for firefighters but a bullish refusal on the part of the union to change

Employers

Employers' secretary Charles Nolda said: "This is the most generous pay offer made by the local authority.

"It's a good way forward for the fire service and I call on the FBU to seize this opportunity to go forward with the employers."

The employers said if the FBU rejected their offer it would be clear "their action is no longer driven by wanting a fair deal for firefighters but a bullish refusal on the part of the union to change".

To say we are disappointed would be the biggest understatement of the year

John McGhee FBU

The union and the employers are holding separate discussions in different London locations and have been only communicating by telephone.

John McGhee, another union negotiator, said his members were furious.

"To say we are disappointed would be the biggest understatement of the year.

"Our patience has been stretched to the absolute limit."

Who will pay?

Although talks are continuing, the chance of any deal being struck on Thursday appears unlikely.

Even if the union accepted the 16%, the employers have another headache.

They can only afford the initial 4% and the government has said repeatedly it will not fund the shortfall for fear of sparking a series of economy-damaging wage claims.

New pay offer

Immediate: 4% April 2003: 3.5% November 2003: 3.5% Total: 16% Old wage: �21,000 New wage: �25,000

Mr Prescott told the House of Commons that would be "unfair" to other public sector workers.

"So I say to the Fire Brigades Union - call off the strike," he said.

"Stay at the negotiating table.

"Work out a deal which is fair to firefighters and fair to all."

Sticking point

The independent review conducted by Professor Sir George Bain, which is backed by the government, concluded a further raise could only be funded by modernisation of the service.

Mr Prescott said that was the sticking point.

"The difficulty is accepting whether modernisation will be part of any agreement - they (FBU) have made it clear it's not," he said.

The strike is due to start at 0900 GMT on Friday.

Military Green Goddess vehicles will again be used to provide emergency cover if the strike goes ahead.

Tory leader Iain Duncan Smith called for troops to be allowed to use the red fire engines and the government to use its emergency powers to keep the public safe.

In a separate development, the Association of Chief Police Officers (ACPO) has said its members will not cross picket lines to take red fire engines for the armed forces to use.

Precisely who goes through a picket line, should it be necessary, is less important than the fact that it happens

Government spokesman

Defence Secretary Geoff Hoon had suggested police could cross picket lines after army chiefs said soldiers would not.

ACPO vice president Chris Fox, the chief constable of Northamptonshire Police, said: "Under the legislative framework currently in effect, police have no part to play in themselves removing red engines from fire stations."

Downing Street insisted the government was prepared to issue instructions to commandeer the red fire engines, but it would not be drawn on how if both the Army and police refused to cross picket lines.

"Precisely who goes through a picket line, should it be necessary, is less important than the fact that it happens," a spokesman said.