Unless properly fixed...

Unless properly fixed, those cars could hide potentially costly trouble for second-hand buyers. And that - along with a possible question mark over future warranty claims - is concerning manufacturers. Now franchised dealers are being told to supply full details of each misfuelled vehicle using online forms.

Car makers have issued technical bulletins giving repair instructions, as no vehicle warranty includes misfuelling damage, and it is almost completely excluded by cover provided by insurance firms. "When a claim for component failure is received, we want to know if misfuelling was a factor," said a Land Rover spokesman. "If we think it was, then we could reject the vehicle owner"s case."

Diesel damage can be severe unless it"s cleaned out and treated, because petrol strips the fuel pump and engine internals, creating metal particles that can wreck the motor.