November, 21 1990. She resigned the next day after failing to win enough votes in the Tory leadership contest.
About Margaret Thatcher
Margaret Hilda Thatcher, Baroness Thatcher was the Prime Minister of the United Kingdom from 1979 to 1990 and the Leader of the Conservative Party from 1975 to 1990. She was the longest-serving British Prime Minister of the 20th century and is the only woman to have held the office. A Soviet journalist called her the "Iron Lady", a nickname that... Wikipedia
October 13, 1925, Grantham, Lincolnshire, England, United Kingdom