Scottish Secretary Helen Liddell has denied that the government is trying to smash the firefighters' strike.

The Fire Brigades Union (FBU) has blamed the government for the collapse of last-ditch talks after an agreement had been reached with the local authority employers.

Scotland's fire cover is now in the hands of the armed forces for the second time after regular crews walked out of their stations at 0900 GMT on Friday, heralding the start of eight days of action.

According to the FBU, an agreement based on a pay rise of 16% over the next year had been on the verge of success, but the government said it could not study the details of the proposed deal before the strike began.

Helen Liddell: "Blank cheque"

Meanwhile, private security guards have been posted at every fire station in the Strathclyde region.

One guard told BBC Scotland: "The firefighters on strike have got to get permission to get on the premises."

Mrs Liddell said that the government could not write a "blank cheque" to pay for the pay deal and needed time to study the costs involved.

She added that after looking at the agreement it was clear that the link between a pay increase and modernisation of working practices had been broken.

She said: "In essence it's a 16% settlement with no strings attached.

"We have been clear all along, fair pay for firefighters, but it must be linked to modernisation."

First Minister Jack McConnell described the strike action as "unacceptable" and called on the FBU to continue talks.

Fire facts

Scotland has 4,588 full-time firefighters 2,799 part-time firefighters 1,200 volunteer firefighters 520 fire engines 30 aerial appliances 14 rescue and emergency vehicles 59 other specialist vehicles 110 Green Goddesses are being used in Scotland Nine Red Goddesses are also in use

Firefighter Bryan Banks, on the picket at Edinburgh's Tollcross Station, said: "The Labour Cabinet fat-cats are stymieing progress at every turn.

Mr Banks, a union branch secretary, added: "These are the same people who took 40% and who are accusing us of destroying the British economy through our claims for a fair wage.

"This now appears not to be about the worth of firefighters but about Tony Blair trying to crush the FBU."

The Convention of Scottish Local Authorities (Cosla) described the talks breakdown as an "absolute tragedy" and one Scottish National Party negotiator who attended the pay talks in London said "government intransigence" had blocked a resolution.

Cosla president Pat Watters said a lack of funds from central government had played a part in the collapse of negotiations.

Civilian fire engines

Angus SNP Councillor Stewart McGlynn said: "We had a deal and the strike was about to be called off when we learned that the government had pulled the rug out from under the talks."

Military personnel, who first went into action during two days of strike action last week, have been providing cover for the firefighters using 50-year-old Green Goddess fire engines.

These have complemented by at least nine "Red Goddesses", old civilian fire engines, some of which have been bought by the Scottish Executive, with others on loan from various brigades.

They are obsolete by today's standards but are still much more sophisticated and capable of delivering water at a much higher pressure than their elderly green counterparts.

No major incidents had been reported by late afternoon on Friday.

Retained firefighters were called assist to Wick airport's fire team when a passenger plane reported problems at about 1500 GMT. It landed safely.