http://www.legislation.gov.uk/id/ukpga/Geo5/21-22/28

http://www.legislation.gov.uk/ukpga/Geo5/21-22/28/section/2931.

Finance Act 1931

An Act to grant certain duties of Customs and Inland Revenue (including Excise), to alter other duties, and to amend the law relating to Customs and Inland Revenue (including Excise) and the National Debt, and to make further provision in connection with finance.