Forecourts are facing fuel shortages as large parts of the country are paralysed by the severe weather conditions. Brian Madderson, chairman of RMI Petrol, said the situation had reached a "critical point".

The association has reported that the snow and exceptionally cold weather has disrupted the fuel supply chain to such an extent that up to 500 independent petrol retailers are threatened with running out of petrol and diesel by the weekend. Rural filling stations away from the main trunk roads have been particularly badly affected.

Road tankers have been unable to leave the main terminals from the Total refinery at Lindsey and from the Jet (Conoco) refinery at Killingholme, both on south Humberside, which is cutting the supply chain off at its knees.

Similar problems have been reported this morning from the refinery terminals at Grangemouth, Falkirk and at Coryton on the north Thames. Fuel companies with facilities in the east of the country are reporting that they are at least two or three days behind normal delivery schedules already.

Madderson said: "We are close to a critical point in what is fast becoming a fuel crisis as well as a weather crisis. Acute problems of supply, particularly of diesel, are being reported by our rural members in the north-east of England and eastern Scotland. A number of filling stations are already reported to be out of fuel.

"The crisis is now spreading south as the weekend unfolds. Every hour that passes, the fuel crisis is intensifying.

"By the end of the weekend, tens of thousands of motorists could have no fuel to go about their daily lives, whether it be getting to work, taking the kids to school, or doing the weekly shop."

A spokesman for BP said deliveries to BP petrol stations and customers from terminals at Coryton and Grangemouth had been severely impacted by the bad weather, with only safe and essential deliveries being made. "Safety is BP’s number one priority so delivery vehicles are being double-manned and are only leaving the terminals to carry out deliveries when it is safe to do so," he said. "This means there are some short periods when some petrol stations are without petrol or diesel but we are working to minimise any disruptions to our customers and apologise for any inconvenience."

Shell sent out a statement which said: "We continue to monitor the road conditions and deliver fuel where it is safe to do so. Where this is not possible all affected sites have been informed.”

A spokesperson for Esso said: "We are working hard to get deliveries to sites in the adverse weather conditions. All Esso terminals are open and our service stations are well stocked. It is possible some might have run out of some grades of fuel due to weather and road conditions. We are unable to confirm where they are because it’s a changing picture."