"For emission purposes vehicles are tested against details shown on the VIN and not the registration plate. Vehicles fitted with a different engine are tested according to which is older, engine or vehicle.

Catalytic convertors were introduced from 1st August 1992 and are compulsory after 1st August 1995. Vehicles first used between 01/08/92 and 31/07/95 are only cat tested if there is an exact match (re engine code) in the analyser database or in the Inservice Emissions book. Vehicles first used on or after 01/08/95 are cat tested using vehicle specific limits if there is an exact match. If there is no exact match it is cat tested using default limits, CO<=0.3%, HC<=200ppm"