All diesel-powered BMWs are now fitted with its “incorrect fuelling protection system” (IFPS) to stop cases of mis-fuelling.

IFPS works by preventing petrol pump nozzles from entering the fuel tank neck of a diesel-powered car. The larger diameter diesel nozzle is able to touch two opposing contact patches that then releases the locking system, but the smaller petrol nozzle is locked out.

The system was initially introduced on 1, 3 and 5-Series, and X3 cars in March, but is now also fitted to 6 and 7-Series and X5 models.

Its introduction is expected to prevent most of the 1,000 cases a year of mis-fuelling that occur on BMW cars which can each cost owners thousands of pounds to rectify.