Retailers report increased sales of petrol cans

Mr Straw rejected allegations that the government's contingency plans had sparked panic buying, saying it was caught "between a rock and a hard place" between scare-mongering and complacency.

He said: "Sometimes if you tell people not to panic, they follow the example of Dad's Army. We are dealing with a difficult issue of public psychology."

But Edmund King, of the RAC Foundation, told Today: "We have heard the government talking about this Task Force, about emergency supplies to the emergency services, so not surprisingly many motorists are thinking if the government are taking emergency steps, we must do the same."

The renewed buying frenzy comes as fuel protesters threaten to launch more demonstrations if the government does not agree to cut fuel duty within the next 10 days.

In a speech on Friday, Prime Minister Tony Blair urged people not to panic-buy and said when Chancellor Gordon Brown makes his pre-Budget report next week there would be no "quick fix" on fuel.

He said he understood everyone wanted cheaper petrol, but warned that cutting duty would mean less money for pensioners, hospitals and schools.

Blair: Economy would suffer

But as the fuel protesters' deadline of 13 November approaches, the familiar scenes of dry petrol stations are threatening to return.

The RAC has warned drivers buying large quantities of fuel and storing it at home is both illegal and dangerous.

Supermarket chain Sainsbury's has reported demand up by 60% and says a third of its 240 stations are closed.

But the company pointed out there was no problem with new supplies coming through.

Oil companies Texaco, Esso, BP and Shell all say they are stepping up deliveries to meet increased demand over the weekend, but maintain there is no general shortage.

Action is due to begin next weekend in the form of a slow-moving convoy of lorries which is expected to take four days to drive from Newcastle to London.

The government says if blockades resume, it will ensure petrol supplies leave fuel depots and will use the Army to make deliveries if necessary.