As Home Secretary Bruce was responsible for the 1872 Licensing Act which regulated pub closing times and regulated the content of beer. He sat as Liberal MP for Merthyr Tydfil 1852-1868 and Renfrewshire 1869-73 before going to the House of Lords in 1873 and leaving the Home Office to serve as Lord President of the Council. The defeat of the Liberals in 1874 ended Bruce’s political career but in later life he was elected a Fellow of the Royal Society and was president in turn of the Royal Historical Society and the Royal Geographical Society.