West Midlands Police has introduced a sticker scheme in an attempt to prevent officers from misfuelling their vehicles.
The force said it was in the process of putting stickers around the fuelling areas of vehicles to advise drivers that they are diesel-only.
The move comes after allegations that the organisation used around £9000 of public money to repair vehicles that had been filled with the incorrect fuel last year.
The force also said it was aiming to improve driver standards.
