Margaret Thatcher Margaret Thatcher Margaret Hilda Thatcher, Baroness Thatcher, (; 13 October 19258 April 2013) was a British stateswoman who served as Prime Minister of the United Kingdom from 1979 to 1990 and Leader of the Conservative Party from 1975 to 1990. She was the longest-serving British prime minister of the 20th century and the first woman to hold that office. A Soviet journalist dubbed her "The 'Iron Lady, a nickname that became associated with her uncompromising politics and leadership style. As Prime Minister, she implemented policies known as Thatcherism. A research chemist at Somerville College, Oxford, before becoming a barrister, Thatcher
Prime minister and in British colonial territories as they developed self-government. In some places alternative titles such as "premier", "chief minister", "first minister of state", "president of the council" or "chancellor" were adopted, but the essentials of the office were the same. By the late 20th century, the majority of the world's countries had a prime minister or equivalent minister, holding office under either a constitutional monarchy or a ceremonial president. The main exceptions to this system have been the United States and the presidential republics in Latin America modelled on the U.S. system, in which the president directly exercises executive authority.