http://www.legislation.gov.uk/id/ukpga/Eliz2/9-10/36

http://www.legislation.gov.uk/ukpga/Eliz2/9-10/36/section/4

Finance Act 1961

An Act to grant certain duties, to alter other duties, and to amend the law relating to the National Debt and the Public Revenue, and to make further provision in connection with Finance.