UK road tax rates
1921 Vehicles not exceeding 6 horsepower - £6 Each extra unit of
horsepower - £1
1934 Horsepower tax reduced from £1 to 15/-
1940 Horsepower Tax raised to £1
1948 A new flat rate tax was imposed: £10
cars registered after 1 January 1947 - £10
cars registered before 1 January 1947 - £7/10/- up to 6hp,
plus £1/5/- for each extra unit of horsepower
* = 1939 to 1941 also available with "War Service" Overprints
All Disc should be printed 3 Inches (75 millimetres) in diameter