Mr Smiths receipt shows that he filled his van with 37 litres of diesel last Monday at Tesco. But after it broke down the next day, a mechanic drained 30 litres of petrol from the tank. Tesco, however, says an investigation has found no issues with the fuel at the store in Sandown Road. Mr Smith, 63, of Foul Anchor, said: I have the receipt to show that I put diesel into my tank at the Tesco store in Wisbech at 7.52am last Monday morning. So how the petrol got into there is a mystery. I want to warn other motorists to be aware that if they used pump five they could be facing a problem. Mr Smiths van is still being repaired by M & W Autos at Wisbech St Mary. It needs a new fuel pump and the injector pump has been damaged. He said: The garage rang me to say there was petrol in the tank. I told them to look for the receipt on the dashboard and there it was, showing I bought 37 litres of diesel. I have been in touch with Tesco, but it will not admit liability. But surely it has a duty of care. Kevin Darnell, a vehicle technician at M & W Autos, said: Our company definitely took petrol out of the diesel in Mr Smiths van. Mr Smith says he travelled 100 miles before the problem came to light. He believes that because diesel is heavier than petrol, his fuel pump used the remaining diesel in the tank before the newly acquired petrol was taken into the engine. So far, Tesco has drawn a blank over the fuel mix-up. A spokesman for the company said: We have investigated this matter and have not found any issues with the fuel at our Wisbech store.