Leonard James Callaghan, Baron Callaghan of Cardiff, (; 27 March 1912 – 26 March 2005), often known as Jim Callaghan, was a British politician who served as Prime Minister of the United Kingdom from 1976 to 1979 and Leader of the Labour Party from 1976 to 1980. To date, Callaghan is the only person to have held all four Great Offices of State, having also served as Chancellor of the Exchequer (1964–1967), Home Secretary (1967–1970) and Foreign Secretary (1974–1976), prior to his premiership. As Prime Minister, he had some successes, but is remembered chiefly for the "Winter of Discontent" of 1978–79. During a very cold winter, his battle with trade unions led to immense strikes that seriously inconvenienced the public, leading to his defeat in a general election by Conservative leader Mar