The blaze, which took place in the car park of Asda in Donnington, on Wednesday(13) afternoon, involved a silver people carrier.
Eye witnesses reported it had pulled onto the petrol forecourt at the store before a staff member noticed the vehicle was alight.
After being alerted the driver managed to move the vehicle to the store's car park, where the flames later engulfed the front end of the vehicle.
The heat from the blaze, which was put out by firefighters, also appears to have damaged a vehicle next to the people carrier.
Fire officers were still at the scene at 3pm dealing with the aftermath of the blaze.