Contingency plans were being finalised today, hours before the first firefighters' strike for a quarter of a century was due to start.
Tens of thousands of firefighters will begin a 48-hour walkout at 6pm after last-ditch peace talks collapsed yesterday.
It means fire cover is likely to be reduced at Chichester, Bognor, Worthing, Shoreham, Horsham, Crawley, Horley, Haywards Heath, East Grinstead, Brighton and Hove, Eastbourne, Hastings, Seaford, Newhaven and Hailsham.
The areas affected will be covered by troops using ageing Green Goddess engines, 16 of which have been allocated to Sussex, to maintain some level of emergency cover.
The dated vehicles have a top speed of 35mph and do not carry the specialist equipment need for cutting people free in road crashes.
But because fire brigade leaders are refusing to let their own equipment be used, soldiers will have to make do.
Ministers say the strike by up to 50,000 firefighters will risk lives and other workers could refuse to work if they believe their safety is at risk.
Paramedics will be prevented from going into burning buildings to treat victims.
Trevor Anderson, director of operations at Sussex Ambulance Service, said he could not say whether lives would be lost but urged people to take extra care when driving.
In East Sussex the strike involves 542 full-time firefighters, 250 retained firefighters and 39 pumps. In West Sussex it is 401 full-time and 327 retained.
Unions have said they will support members taking action, which could spark disputes across British industry.
Fire Brigades Union general secretary Andy Gilchrist met Deputy Prime Minister John Prescott last night to discuss the level of cover firefighters will provide in the event of a major incident such as a terrorist attack.
The dispute, which has been smouldering since April, has flared up into the biggest industrial relations crisis since Labour returned to power.
Mr Gilchrist accused the Government of intervening twice to prevent a settlement and said it had successfully provoked a national strike.
He said: "I am extremely angry. We have no alternative other than to reject the insulting offer which has been made to some of the finest public servants in the world."
Further strikes, each lasting eight days, will follow on November 22 and on December 4 and 16 unless the increasingly bitter dispute is settled.
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