The 1979 United Kingdom general election was held on 3 May 1979 to elect 635 members to the British House of Commons. The Conservative Party, led by Margaret Thatcher, ousted the incumbent Labour government of James Callaghan with a parliamentary majority of 43 seats. The election was the first of four consecutive election victories for the Conservative Party, and Thatcher became the United Kingdom's and Europe's first elected female head of government. The previous parliamentary term had begun in October 1974, when Harold Wilson led Labour to a majority of three seats, but within eighteen months he had resigned as Prime Minister to be succeeded by James Callaghan, and within a year the government's narrow parliamentary majority had gone. Callaghan had made agreements with the Liberals, the Ulster Unionists, as well as the Scottish and Welsh nationalists in order to remain in power. However, on 28 March 1979 following the defeat of the Scottish devolution referendum, Thatcher tabled a motion of no confidence in Callaghan's Labour government, which was passed by just one vote (311 to 310), triggering a general election five months before the end of the government's term. The Labour campaign was hampered by the series of industrial disputes and strikes during the winter of 1978–79, known as the Winter of Discontent, and the party focused its campaign on support for the National Health Service and full employment. After intense media speculation, Callaghan had announced early in the autumn of 1978 that a general election would not take place that year having received private polling data which suggested a parliamentary majority was unlikely. The Conservative campaign employed the advertising agency Saatchi & Saatchi and pledged to control inflation as well as curbing the power of the trade unions. The Liberal Party was damaged by allegations that its former leader Jeremy Thorpe had been involved in a homosexual affair, and had conspired to murder his former lover. The Liberals were now being led by David Steel, meaning that all three major parties entered the election with a new leader. The election saw a 5.2% swing from Labour to the Conservatives, the largest swing since the 1945 election, which Clement Attlee won for Labour. Margaret Thatcher became Prime Minister, and Callaghan was replaced as Labour leader by Michael Foot in 1980. Results for the election were broadcast live on the BBC, and presented by David Dimbleby and Robin Day, with Robert McKenzie on the "Swingometer", and further analysis provided by David Butler. It was the first general election to feature Rick Wakeman's song "Arthur" on the BBC's coverage. Future Prime Minister John Major entered Parliament in this election. Jeremy Thorpe, Shirley Williams and Barbara Castle all left Parliament as a result of this election.