In 1956, Marcia Williams, as she was then known, became private secretary to Harold Wilson, Member of Parliament for Huyton, a position she retained until 1964, when she rose to be his political secretary and head of the political office in his position as leader of the Labour Party and as prime minister from 1964 until 1970 and again from 1974 to 1976. Falkender claims that she first met Wilson when he offered her a lift when she was standing at a bus stop. Wilson's press secretary Joe Haines claims that the pair first met at a dinner with the Soviet premier, Nikita Khrushchev, at which Khrushchev and the Labour MP George Brown had a drunken argument, which Williams took down in shorthand. Wilson reportedly drove her home after dinner. In 1970 she was appointed a Commander of the Order of the British Empire (CBE).