When it became clearer that Labour would not be staying in power late on Tuesday, Gordon Brown tendered his resignation in an emotional speech in front of Downing St, before heading to Labour HQ.
On Monday, Brown announced he would stand down in September to facilitate working with the Lib Dems in a coalition.
But talks between Labour and the Lib Dems failed, and to the possible ire of progressive Lib Dems, Clegg sided with the Conservatives.
MP Dianne Abbott told the BBC after Cameron's move into the PM's official residence that 'the rainbow coalition' required for a left-wing alliance to govern- with Labour, the Lib Dems, and a host of smaller parties- could not have worked.
She said unelected Labour associates such as Lord Mandelson had been attempting to drive the process, not grasping the significance of Labour's poor showing at the polls.
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Browns early months were a success. But he never recovered from the financial crisis.
Brown steps down
The son of a Presbyterian minister, always uncomfortable in front of the cameras, Brown laid out what he saw as the proper job of a prime minister.
A man they said always failed to show his human side, saving his best for last.
'I love the job for it's potential', Brown said on Tuesday night.
'Not for its prestige entitlement and ceremony, which I do not love at all.'
The job was always second in importance to being a husband and father, Brown said, appearing with his wife and two young sons, sporting matching blazers.
Cameron then travelled to Buckingham Palace to be confirmed PM by the Queen.
Until a leader is elected, Harriet Harman will lead the party. Speculation over the next leader, however, was already rife. Former Foreign Secretary David Miliband and Former Schools Secretary Ed Balls have been touted as leadership contenders.
Brown announced he'd step down in Monday in order to woo the Liberal Democrats to his Labour Party - but the prospect of working with an 'illegitimate' party was clearly too much for the Lib Dem kingmakers.
But before his rivals did a deal, Brown told the Queen's staff he would resign, advising the opposition to form a government.
Tories offer electoral reform referendum
Tory (Conservative) negotiator and MP William Hague on Monday said his party was prepared to offer a referendum on electoral reform, a key demand of the Lib Dems.
"In the interests of trying to create a stable, secure government, we will go the extra mile and we will offer to the Lib Dems in a coalition government the holding of a referendum on the Alternative Voting system," Hague said on Monday.
The offer came shortly after Prime Minister Gordon Brown announced his Labour party was opening formal talks with the Lib Dems on a power-sharing deal, and that he would step down to facilitate those talks, by September.
Clegg has now sided with the Lib Dems, and Britain has a new prime minister.
