Thousands of motorists in Britain's south east have been left with engine problems after buying unleaded fuel from filling stations at various Tesco and Morrisons supermarkets.
The petrol at fault has been causing engine misfires and total combustion failures, sometimes just a few hundred yards from the supermarket forecourt from which it was bought.
The fuel is believed to have come from a single contaminated batch that originated at a distribution terminal in Essex, and seems to be concentrated at forecourts in the Essex, Hertfordshire, Buckinghamshire and Middlesex areas. However, cases have been reported as far north as Fife and as far south as Dorset.
Problem gathers momentum while cars break down
Although the story has gathered enormous momentum in the past 24 hours, it has been building for weeks. Autocar has learned that garage service departments are carrying out incredible numbers of repairs on cars that have been damaged by contaminated fuel.
The standing stock of lambda sensors, the component that's most likely to be damaged, is now at an unprecedented low in the national Vauxhall, Ford and Peugeot franchised dealer network.
One service manager at a Mercedes franchise in Hertfordshire told us that he'd repaired 15 cars with contaminated fuel in the past four days.
"It's terrible," he said. "The number of cars coming in is unbelievable - all of them have fuel that has been contaminated. Half of them came in after they refuelled at Tesco down the road. We don't know whether it is water or something else, but it is clear there is a problem."
"We've had to flush out their fuel tanks and fuel lines and then replace the oxygen sensors," he explained. "Customers are paying between £800 and £1000, and it's a shame for them because their warranties do not cover this sort of thing."