Margaret Thatcher was a British Conservative politician who served as leader of the opposition (1975 - 1979). In February 1975 she ousted Edward Heath as leader of the conservative party. As leader she moved party policy sharply to the economic right, endorsing the views of Hayek, Friedman and the Chicago school of free market economics. Following the electoral defeat she stayed on as leader but was challenged in November 1978 by Michael Heseltine. Thatcher lost the first ballot by a single vote, and declined to contest the second ballot.