Exempt vehicles
Various classes and uses of vehicle are provided with a tax disk without charge.
Vehicles constructed before 1 January 1973 are eligible for a free vehicle licence under the "Historic Vehicles" legislation. This is due to the age of the vehicle and a presumption of limited mileage. Initially this was a rolling exemption applied to any vehicles over 25 years old, however the cutoff date was frozen in 1997. The change to "pre-1973" was unpopular in the classic motoring press, and a number of classic car clubs are campaigning for a change back to the previous system.[citation needed] In 2006 there were 307,407 vehicles in this category:[14]
Other exempt vehicle (broadly in descending order of total number) include:
* Vehicles registered to disabled people (1.12 million vehicles).[15]
* Emergency vehicles (includes police cars, fire-engines, and ambulances and other health-service vehicles). (450,000 vehicles)[16]
* Vehicle registered to ex-soldiers who are in receipt of war pensioners’ mobility supplement (18,340 vehicles).[17]
* Band A cars (306 vehicles in 2006, but rising fast).[18]
* Ministerial cars.[19]
* Vehicles operated by the Government Car and Despatch Agency.[16]
* Cars imported by american soldiers stationed in Britain.[16]
* Road construction vehicles.[20]
* Vehicles owned by the crown for the use of Queen Elizabeth II and other members of the royal family.[16]
http://en.wikipedia.org/wiki/Vehicle_excise_duty