Motorists are being urged not to panic-buy fuel as hundreds of fuel tanker drivers stage a four-day strike over pay.
The industrial action, by drivers who deliver fuel to Shell garages across the UK, will affect one in 10 of Britain's 9,500 filling stations but the Government and the oil and transport industries have urged motorists not to panic-buy fuel.
Prime Minister Gordon Brown refused to rule out calling in the Army to keep fuel flowing and pledged that ministers were willing to do "everything we can" to stop petrol pumps running dry.
Union leaders warned fuel would start to run out "almost immediately" and all Shell's forecourts would be affected within 24 hours.
But the UK Petrol Industry Association (UKPIA), which represents oil refiners, said stocks at forecourts across the UK were at normal levels and most garages would have around four days of supplies.
Business Secretary John Hutton said it was "extremely disappointing" that the talks had broken down and he urged both sides to resume negotiations.
He added: "Our advice to motorists now is just to buy the fuel they actually need."
Striking tanker drivers will mount picket lines at a number of Shell sites based at oil terminals including Stanlow in Merseyside, Avonmouth, Plymouth, Pembroke, Cardiff, Kingsbury, Basildon, Grangemouth, Aberdeen, Inverness, Jarrow and a small site at Luton Airport.
Bosses at Hoyer and Suckling Transport, the two firms involved in the dispute, said they had offered an increase for this year of 7.3% backdated to January 1 2008, which would take average earnings to over £39,000, with a further 6% increase from January 1 2009, which would take earnings to around £41,500.
Len McCluskey, assistant general secretary of Unite, confirmed a 7% pay rise had been offered but denied this would take pay to more than £41,000 and described it as inadequate when Shell is making profits of £1.3 billion a month.
