3617857 Margaret Thatcher as leader of the Conservative Party, 1975 (b/w photo) by Trikosko, Marion S. (fl.1964); Private Collection; (add.info.: Margaret Hilda Thatcher (nee Roberts 1925-2013) was Prime Minister of the United Kingdom 1979-1990 and Leader of the Conservative Party 1975-90. She was the longest-serving British prime minister of the 20th century and the first woman to have been appointed.); American, out of copyright.