BRITAIN'S firefighters returned to work last night after a 48-hour pay strike - but time appeared to be running out to avoid an eight-day walkout.

Seven people died in house fires while the 50,000 firemen and women were on picket lines and the military dealt with more than 2,500 emergency calls between 6pm on Wednesday and 6pm last night.

In the North-East and North Yorkshire, more than a quarter of emergency calls were malicious, Army officials revealed.

During the strike, the Green Goddesses responded to 197 emergencies in the region, 49 of which were hoaxes. Many more hoax calls were made but not responded to.

An Army spokesman revealed that the majority of hoax calls were in the early hours of the strike and thanked the media for highlighting the problem.

"It really dropped off and that's been pretty much across the board. I think what the media has said has probably helped quite a bit. It's made people sit up and think."

Telephone companies warned last night malicious callers could and would be tracked down.

When a 999 call is made, the caller's number is always displayed on the operator's screen, even if they dial 141 first to try to avoid detection.

BT spokesman Paul Dorrell said operators then pass the call on to the appropriate regional control room. If police discover the call was malicious, operators can immediately find an address for landline numbers.

"All 999 calls are recorded so tapes can be passed to police and voice recognition used to trace callers," he said.

Police and fire chiefs across the region said they were satisfied with the way they had dealt with the strike.

Chief Superintendent Jeff Evans, who headed the operation on Teesside, home to Europe's biggest petro-chemicals complex, said: "All staff were working in unfamiliar roles. They displayed true commitment and professionalism throughout. I am pleased that no injuries have been reported to any members of the public or military fire crews."

Relations between the Government and the Fire Brigades Union (FBU) reached a new low during the action, with strong attacks on the walkout from Prime Minister Tony Blair and his deputy, John Prescott. Mr Blair warned last night that the FBU would be "deeply irresponsible" to go ahead with its planned eight-day strike from next Friday.

"It would put lives in danger, it would be wrong," said Mr Blair. "And from the Government's perspective, we have to do everything we can to protect the public - and we will."

The Government has warned it might order troops to take control of fire engines if the strikes continue and there have suggestions of moves to outlaw strikes in the fire service.

Fire Brigades Union leader Andy Gilchrist suggested last night that an offer of 16 per cent - which the employers were believed to be preparing in the summer before being stopped by the Government - would be a good "benchmark" for resolving the dispute, despite the FBU's 40 per cent pay claim.