Former Prime Minister of Britain dies of stroke “It is with great sadness that Mark and Carol Thatcher announced that their mother Baroness Thatcher died peacefully following a stroke this morning,” Thatcher spokesperson Lord Bell said in a statement. Thatcher, an outspoken woman known to many as “The Iron Lady,” was 87. She led Britain’s Conservatives to three election victories from 1979 to 1990, the longest continuous period in office