Sir Alan Charles Maclaurin Mackerras, AC, CH, CBE (/məˈkɛrəs/; 17 November 1925 – 14 July 2010) was an Australian conductor. He was an authority on the operas of Janáček and Mozart, and the comic operas of Gilbert and Sullivan. He was long associated with the English National Opera (and its predecessor) and Welsh National Opera and was the first Australian chief conductor of the Sydney Symphony Orchestra.