Westcountry filling stations could run out of fuel within hours of blockades by striking tanker drivers, experts say.
Petrol stations in the region have already reported panic buying of fuel after the Government told motorists to stockpile supplies ahead of industrial action.
Unions are yet to confirm whether the 80 drivers who supply fuel to Devon, Cornwall, Somerset and Dorset from a single terminal at Plymouth are to walk out over safety fears.
But business leaders say the fallout has already damaged tourism ahead of the Easter getaway, with holidaymakers reluctant to travel for fear they will be stranded.
Dave Springbett, regional officer for the Unite union in Plymouth, said garages in the four counties would “start drying up within hours”.
He predicted the big supermarkets “won’t take long to run out” and said smaller independents no longer had the cashflow to fill their tanks to the brim. “There are not the reserves on the ground anymore – if everybody went to fill up their tanks now we would start to run out.”
Tim Jones, chairman of the Devon and Cornwall Business Council, warned that “well-managed wildcat” strikes would inflict “maximum pain”.
Mr Jones revealed tourist bosses had reported bookings down and customers asking about “contingency plans”.
“People are nervous about what they will do if they get down here and can’t fill up with enough fuel to get back,” he added.
“We just cannot afford to have an economic shock like this – whatever we have got to do must be done – forget the rights and wrongs, we cannot have the disruption.”
Cabinet minister Francis Maude was criticised as reckless by road campaigners and firefighters yesterday for urging motorists to “fill up a jerry can”.
The Prime Minister convened a meeting of the “Cobra” crisis committee as plans were drawn up to draft in the military. The Ministry of Defence refused to confirm whether a naval fuel depot at Torpoint would be included in the emergency plan, which has seen soldiers trained to drive tankers.
David Cameron also recommended “contingency plans” as up to 2,000 Unite members threaten to halt deliveries in protest at their pay and conditions. The trade union said the dispute was not about wages but “minimum standards of health and safety”.
Mr Springbett blamed oil companies and big supermarkets for “cracking the whip” and said “pressure to meet unreachable targets” was “potential for disaster”.
“It is not about greed but drivers protecting themselves and the general public on the roads,” he added.
Transport analysts said the fuel network in the region was almost entirely supplied from the Cattedown terminal in Plymouth, and that panic buying could exhaust supplies “before strikes even start”.
Retailers in Devon reported a surge in demand on forecourts yesterday.
The isolated independent filling station at Clovelly Cross, near Bideford, which is more than 20 miles away from its nearest rival, said it had sold about 50 per cent more than usual.
Dorothy Bailey, who owns the garage with her husband, said: “I have noticed we have been getting big fill-ups – I think it’s holidaymakers.
“We are wondering how it is going to affect us and holding our breath – with us being out of the way we will not be the first priority for deliveries.”