2010 United Kingdom general election

The 2010 United Kingdom general election was held on Thursday 6 May 2010, with 45,597,461 registered voters entitled to vote to elect members to the House of Commons. The election took place in 650 constituencies across the United Kingdom under the first-past-the-post system.

The election resulted in a large swing to the Conservative Party, the largest seen since 1945, when Labour won a landslide victory against the incumbent Conservative government. The Labour Party lost their 66-seat majority, losing nearly 170 seats, their worst result since 1935. By contrast, the Conservative Party led by David Cameron more than doubled its seats from 2005, which gave Cameron the largest Conservative majority since 1983, an election in which the Conservatives also won 397 seats.

For the leaders of all three major political parties, this was their first general election contest as party leader. Prime minister Gordon Brown had taken office in June 2007 following the end of Tony Blair's 10-year reign as prime minister and 13 years as leader of the Labour Party, while David Cameron had succeeded Michael Howard in December 2005 and Nick Clegg had succeeded Menzies Campbell (who never contested a general election) in December 2007.

None of the three main party leaders had previously led a general election campaign, a situation which had not occurred since the 1979 election. During the campaign, the three main party leaders engaged in the first televised debates. The Liberal Democrats achieved a breakthrough in opinion polls after the first debate, in which their leader Nick Clegg was widely seen as the strongest performer. Nonetheless, on polling day their share of the vote fell by nearly 4% and they lost nearly a third of their seats, primarily to the Conservatives. As a consequence, Nick Clegg would resign as leader shortly afterwards, and Vince Cable would subsequently become party leader. Brown would also resign after his party's disastrous defeat, resulting in a leadership contest won by Ed Miliband. Cameron would go on to become Prime Minister, the first Conservative to do so since the 1997 general election, in which Conservative Prime Minister John Major was toppled in a landslide defeat.