GARAGES are struggling to deal with an influx of cars which are feared to have broken down as a result of "contaminated" petrol sold on supermarket forecourts.

Thousands of motorists are thought to have been affected by the suspect petrol, which is now the subject of an investigation by trading standard officials.

Drivers said they had experienced problems after buying petrol from Tesco outlets in the south of England, although there were reports it could have spread across the country.

The Society of Motoring Manufacturers (SMMT) stressed the urgency of finding the source of the potential contamination, which was still unclear.

Chief executive Christopher MacGowan said: "It is a very worrying problem. Down to the present moment, the real difficulty is absolutely identifying what has happened."

He said: "It appears there is a rogue load of petrol in the United Kingdom at the present moment but until we actually can track down exactly where it has come from and also what the precise problem with it is, it's very difficult to give meaningful advice to drivers.

"What we have got to do is establish where the problem lies and where we go from there. At the moment the answers are far from satisfactory for you and I as a driver."

The petrol has been affecting oxygen sensors, which are part of the engine management system and help the car run smoothly if it is operating normally or help it shut down if there is a problem.

Mr MacGowan said there had been a run on the components in recent days, leaving some drivers with their cars off the road for two to three days because a replacement was not available. The problem had come "completely out of the blue", he said, adding: "I have been in this industry for many years and I cannot remember a similar occurrence on this scale."

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