David Cameron has returned to Downing Street with the Tories having defied polls and won the general election.
The Conservatives made gains in England and Wales and are forecast by the BBC to secure 331 seats in the Commons, giving them a slender majority.
Labour leader Ed Miliband said he would stand down on Friday, saying his party must "rebuild" with a new leader.
Lib Dem leader Nick Clegg has also said he will quit, with his party set to be reduced from 57 to eight MPs.
UKIP leader Nigel Farage is also quitting after he failed to win Thanet South, losing by nearly 2,800 votes to the Conservatives.