Surtax
（重定向自Supertax）
A surtax may be a tax levied upon a tax, or a tax levied upon income.
In 1929, Supertax (which had been introduced in the Finance Act 1909 at the rate of 6 old pence in the pound (2.5%) on incomes over 5000 per year) was renamed Sur-tax. By 1934, the rate was variable from 1 shilling to 7 shillings and sixpence in the pound (5% to 37.5%). It was replaced by income tax in 1973.