Britain's national election has denied all three major parties an outright majority, meaning the first so-called hung Parliament since 1974.
What is a hung Parliament?
It's an unusual situation in which no political party wins more than half the 650 House of Commons seats - enough to pass laws even if all opposition lawmakers vote against them. The last time an election left Britain with a hung Parliament was 1974.
Under British convention, the prime minister Gordon Brown as the incumbent leader is offered the first chance to seek support from his rivals to form a coalition government, or to seal a pact whereby rivals would vote in line with his party on key laws. This would be controversial, as Mr Brown's Labour could rank second, or even third, in the popular vote.
Mr Brown is most likely to resign as prime minister. He could hang on until the first meeting of Parliament on May 18, but the opposition would likely attempt to force a motion of no confidence in his government, or simply vote down Brown's first legislative program when it is presented on May 25. At that stage, or earlier if Mr Brown quits, the queen invites the leader of the largest party to form a government - almost certain to be David Cameron's Conservative Party.
Mr Cameron would have a choice. Depending on how far short he is from a majority, he could attempt to strike a pact or enter a coalition with Nick Clegg of the Liberal Democrats, or a minor party. Alternatively, he could serve for a limited time as head of a minority government, knowing his rivals would find it risky to vote down his legislative program immediately. Mr Cameron may bet that his rivals wouldn't want to trigger an immediate second election - which could anger the public. His rivals also lack the funds to pay for another campaign right now. But Mr Cameron would struggle to win votes on contentious laws, and would likely seek a second election within six to 12 months to attempt to win a majority.
After the February election, the incumbent Conservative prime minister Edward Heath spent four days trying to build a coalition, but failed and quit. Labour, which had the largest number of seats, formed a minority administration which lasted about seven months before a second election, in which Labour claimed a majority of three. * AP