British prime minister James Callaghan was defeated by one vote in a vote of no confidence after his government struggled to cope with widespread strikes during the Winter of Discontent.

Leonard James Callaghan, Baron Callaghan of Cardiff was a British statesman and Labour Party politician who served as Prime Minister of the United Kingdom from 1976 to 1979 and Leader of the Labour Party from 1976 to 1980. Callaghan is the only person to have held all four Great Offices of State, having also served as Chancellor of the Exchequer from 1964 to 1967, Home Secretary from 1967 to 1970 and Foreign Secretary from 1974 to 1976. He was a Member of Parliament (MP) from 1945 to 1987.

A vote of no confidence in the British Labour government of James Callaghan occurred on 28 March 1979. The vote was brought by the Official Opposition leader Margaret Thatcher and was lost by the Labour government by one vote, which was announced at 10:19 pm. The result mandated a general election that was won by Thatcher's Conservative Party. The last time an election had been forced by the House of Commons was in 1924, when Ramsay MacDonald, the first Labour prime minister, lost a vote of confidence. Labour politician Roy Hattersley later remarked that the vote marked "the last rites" of Old Labour. Labour did not return to government for another eighteen years, with New Labour ideology. The BBC has referred to the vote as "one of the most dramatic nights in Westminster history".

The Winter of Discontent was the period between late September 1978 and February 1979 in the United Kingdom characterised by widespread strikes by private, and later public sector trade unions demanding pay rises greater than the limits Prime Minister James Callaghan and his Labour Party government had been imposing, against Trades Union Congress (TUC) opposition, to control inflation. Some of these industrial disputes caused great public inconvenience, exacerbated by the coldest winter in 16 years, in which severe storms isolated many remote areas of the country.