David Cameron has won an unexpected majority in the UK's parliamentary elections, overturning poll predictions and sweeping the Conservatives to power, as three of his election rivals quit following their disastrous turnout at the polls.

The Conservative Party managed to secure 326 seats after 643 constituencies were counted, to the Labour party's 230 seats, and eight for the Liberal Democrat party.

"This is clearly a very strong night for the Conservative Party," Cameron said.