Third Thatcher ministry to make way for a leader more likely to win the next general election. Her successor was the Chancellor of the Exchequer John Major, who was elected on 27 November 1990, and who at 47 became the youngest Conservative Prime Minister of the 20th century. <section begin="June 1987 to July 1989" /> <section begin="July 1989 to November 1990" /> Members of the Cabinet are in bold face. Third Thatcher ministry Margaret Thatcher was Prime Minister of the United Kingdom from 4 May 1979 to 28 November 1990, during which time she led a Conservative government. She was the first woman
Margaret Thatcher of the Hadley Centre for Climate Research and Prediction, the establishment of the Intergovernmental Panel on Climate Change, and the ratification of the Montreal Protocol on preserving the ozone. Thatcher helped to put climate change, acid rain and general pollution in the British mainstream in the late 1980s, calling for a global treaty on climate change in 1989. Her speeches included one to the Royal Society in 1988, followed by another to the UN General Assembly in 1989. However, after retiring as Prime Minister, she became sceptical about climate change policy and rejected climate alarmism. Thatcher appointed Lord Carrington, a