Claim: Centre Party's Martti Miettunen, served as a cabinet minister for 4,300 days, the eighth-longest period of service in Finnish political history, became Prime Minister on 30 November 1975 and left office on 29 September 1976.
Evidence: Martti Juhani Miettunen (17 April 1907 – 19 January 2002), was a Finnish politician who served twice as Finland's prime minister, from 1961 to 1962 and again from 1975 to 1977.