Premiership of Margaret Thatcher

Margaret Thatcher's tenure as Prime Minister of the United Kingdom began on 4 May 1979 when she accepted an invitation from Queen Elizabeth II to form a government, succeeding James Callaghan of the Labour Party, and ended on 28 November 1990 upon her resignation. Thatcher, who had been Leader of the Conservative Party since her election in 1975, had led the Conservative Party to victory at the 1979 general election, and won landslide re-elections for the party in 1983 and in 1987.

Source: Wikipedia — Premiership of Margaret Thatcher (CC BY-SA 4.0)