DRIVERS in the region were among the thousands of worried motorists who reported engine problems linked to the fuel contamination crisis.

An investigation has been launched by Trading Standards officers after motorists said they had experienced problems after buying petrol from some service stations and supermarkets.

Last night, industry sources said silicon contamination may have caused the scare.

It is said traces of the chemical were found in preliminary tests on batches of suspect unleaded petrol.

But they stressed that although silicon was found, it was not yet known what form it was in, where it came from or if it was the cause of the breakdowns.

Dr Richard Pike, chief executive of the Royal Society of Chemistry, said silicon in its most basic form was an unlikely culprit.

He said: "The heart of this is quality control assurance and the possibility that chemicals not usually used in the oil industry have contaminated the petrol.

"It may be something in the base of a container that was not washed out. That is one way the contamination could have got in."

Reported problems include misfiring, juddering and a loss of power, possibly caused by engines switching to emergency settings after an exhaust sensor is damaged.

Some owners said they faced bills of up to £1,000, but experts said a typical repair should cost about £100.

Worried drivers bombarded motoring organisations with phone calls yesterday, with the number of people asking the AA for advice more than double that of normal at times.

Patrols also reported a significant increase in the number of vehicles with damage, possibly caused by faulty fuel.

A spokesman said: "We are desperate to be able to tell our members and motorists at large exactly what is going on.

"We are being inundated with calls from people asking us if it is safe to go to petrol stations, and which ones they should be going to."

Broadcasters were also deluged with complaints, with the BBC receiving more than 4,000 emails and text messages from drivers complaining of problems.

Although the problems appear to be concentrated in the South-East and the Midlands, some motorists in the North-East also said their vehicles may have been affected.

Government organisation Consumer Direct told The Northern Echo it had received several calls from people in the North-East.

Stockton Borough Council said six motorists had complained to its Trading Standards department.

Tesco and Morrisons, which have been at the centre of the bulk of complaints, said tests found no problems with their fuel.

Green Energy, an oil company that supplies the stores, has also tested its supplies and found it meets national standards.

Trading Standards officers are making spot-checks on fuel at forecourts in Cambridgeshire, Kent, Essex and Milton Keynes, with results expected today