Tesco today apologised to motorists whose cars broke down after a tanker driver accidentally put diesel into petrol pumps at one of its filling stations.
The supermarket giant has offered to pay for repairs following the gaffe at its Catterick Garrison garage in North Yorkshire.
Around 25 drivers are believed to have been affected in the mix-up on Thursday, but the retailer says it may take some time to establish exact numbers.
A Tesco spokesman said: "There has been an isolated incident where a small number of customers received the wrong fuel when filling up at our store.
"We are in contact with customers affected to apologise and arrange any necessary repairs to their vehicles."
He stressed that there was no issue with fuel contamination at Tesco petrol stations.
The AA said it was the second time in a month forecourt tanks had been filled with the wrong fuel.
Spokesman Luke Bosdet said: "It seems to be happening more often than we'd expect.
"It's very irritating to find that your car has conked out and it does take time to drain the tank. But supermarkets tend to be very good at dealing with the problem."
Last month, a similar blunder by a tanker driver at Sainsbury's in Salford, Greater Manchester, affected 44 cars and caused around £14,000 of damage.