Please go to the link below and add your name to petition the
government to change the static date for road tax exemption:

http://petitions.pm.gov.uk/historiccartax/

Detail from the petition writer...
Currently cars have to have been constructed before a set date - the
1st January 1973 to be eligible for historic car tax exemption. We the
undersigned would like the date to be moved as it has been fixed for a
number of years. A number of cars which were built in British
factories are becoming few and far between and we would like the
Government to help preserve these cars by offering an extension on the
current exemption date.