Brendan John Nelson (born 19 August 1958) is a former Australian politician and former federal Opposition leader. He served as a member of the Australian House of Representatives from 1996 federal election until 16 September 2009 as the Liberal member for Bradfield, a northern Sydney seat. A doctor by profession, he came to public prominence as the Federal President of the Australian Medical Association (1993–1995), and served as a Minister in the third and fourth terms of the Howard Government, serving as Minister for Education, Science and Training (2001–2006) and Minister for Defence (2006–2007). Following the 2007 federal election, at which the Howard Government was defeated, Nelson was elected leader of the federal Liberal parliamentary group in a contest against former Minister for Environment and Water Resources Malcolm Turnbull, and became the Leader of the Opposition on 3 December 2007. On 16 September 2008, in a second contest following a spill motion, Nelson lost the leadership of the Opposition and the Liberal Party to Turnbull. On 25 August 2009 he announced his retirement from politics, sparking a 2009 Bradfield by-election.