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
Office of the Prime Minister (Thailand) Office of the Prime Minister (Thailand) The Office of the Prime Minister (; ; Abrv: OPM) is the central executive agency in the Government of the Kingdom of Thailand. It is classified as a cabinet department and is led by its own minister. Its main responsibility is to assist the Prime Minister of Thailand in the role of head of government and chair of the cabinet of Thailand. As the central executive agency, the Office of the Prime Minister is in charge of the coordination and management of the executive branch of the government of Thailand. It assists prime ministers