The main reason that there is not a database available to the public regarding vehicles that are used as taxis is that licences are issued on a local rather than national level. Even if a local database were available it would not prevent a vehicle from being sold outside the area where it was originally registered as a taxi. We would suggest paying for a vehicle history check which can provide information that indicates a previous business use, as well as checking for visual clues such as heavy wear on the driver's seat, high mileages and marks on the rear where additional plates have been attached. Look at www.vehicleancestry.co.uk/