Prime Minister of Australia prime minister, otherwise William McMahon63. Robert Menzies was the oldest person to ever be prime minister, leaving office at 71 years old. The longest-serving Prime Minister was Sir Robert Menzies, who served in office twice: from 26 April 1939 to 28 August 1941, and again from 19 December 1949 to 26 January 1966. In total Robert Menzies spent 18 years, 5 months and 12 days in office. He served under the United Australia Party and the Liberal Party respectively. The shortest-serving Prime Minister was Frank Forde, who was appointed to the position on 6 July 1945 after the death of
Parliamentary Private Secretary to the Prime Minister British Army. Parliamentary Private Secretary to the Prime Minister The Parliamentary Private Secretary to the Prime Minister is a position serving the Prime Minister of the United Kingdom. The holder of the office is widely viewed as the Prime Minister's "eyes and ears" on the backbenches, serving as a liaison to the Prime Minister's parliamentary party. The Parliamentary Private Secretary is also responsible for meeting with members of Parliament when the Prime Minister is unavailable, and accompanying the Prime Minister to, and assisting them with preparations for Prime Minister's Questions. The Parliamentary Private Secretary can become a highly powerful and