David Cameron is preparing for another term as Prime Minister, as the General Election put his Conservative Party on the brink of securing an absolute majority in the House of Commons.
A dramatic night saw the Scottish National Party sweep Labour out of almost all its strongholds north of the border, while Liberal Democrats suffered savage losses and question marks were raised about the future of Ed Miliband, Nick Clegg and Nigel Farage.
Mr Cameron all but declared victory in a speech after being returned as MP for Witney, in which he set out his intention to press ahead with an in/out referendum on Britain's membership of the European Union and to build on the economic foundations laid by the coalition since 2010.
"My aim remains simple - to govern on the basis of governing for everyone in our United Kingdom," he said.
He made clear he was determined not to allow the rising tide of nationalism to lead to the break-up of the United Kingdom, saying: "I want to bring our country together, our United Kingdom together, not least by implementing as fast as we can the devolution that we rightly promised and came together with other parties to agree both for Wales and for Scotland.
"In short, I want my party, and I hope a Government I would like to lead, to reclaim a mantle that we should never have lost - the mantle of One Nation, One United Kingdom. That is how I will govern if I am fortunate enough to form a government in the coming days."
A clearly crestfallen Mr Miliband came close to conceding defeat in a speech after holding his seat of Doncaster North, describing the election as "very disappointing and difficult" for Labour and saying that "the next government" would have a huge responsibility to hold the United Kingdom together.
Mr Miliband made no comment about his own position as he left for Westminster, though senior figures including veteran former minister Jack Straw said he would have to "make up his mind about his future" as party leader.
Liberal Democrats suffered painful reversals in what Mr Clegg termed a "cruel and punishing" night, with senior figures including Business Secretary Vince Cable, Treasury Chief Secretary Danny Alexander, Energy Secretary Ed Davey and justice minister Simon Hughes ejected from the Commons by voters.
Mr Clegg held onto his seat of Sheffield Hallam, but appeared set to stand down as leader, saying he would speak to party colleagues "about the implications of this election both for the country and the party I lead and for my position in the Liberal Democrats" on his return to Westminster later this morning.
An exit poll predicted the Conservatives would win 316 seats to Labour's 239, but the academic who led the operation said that early results suggested Mr Cameron's party could reach the magic 326 number needed to command an absolute majority in the House of Commons.
A Press Association forecast after 460 declarations suggested the Tories could win 329 seats, to Labour's 230 and Liberal Democrats' 10. Labour's tally looked set to be well below the 258 MPs secured by Gordon Brown in the disastrous 2010 election.
As the SNP swept up one Labour stronghold after another - toppling the party's Scottish leader Jim Murphy and shadow foreign secretary Douglas Alexander and snatching the former constituency of ex-prime minister Mr Brown - the party's former leader Alex Salmond said there had been an "electoral tsunami" north of the border.
Mr Salmond, who returned to Parliament as MP for Gordon, said: ''There's going to be a lion roaring tonight, a Scottish lion, and it's going to roar with a voice that no government of whatever political complexion is going to be able to ignore."
But the party was denied the clean sweep some had predicted north of the border, as the Liberal Democrats held Orkney and Shetland, Ian Murray held on to Edinburgh South for Labour, and David Mundell remained the only Tory MP in Scotland, holding on to Dumfriesshire, Clydesdale and Tweeddale.
There were signs of dissent in Labour ranks, with respected backbencher John Mann tweeting: "Can't say that Labour leadership weren't warned repeatedly - those who even bothered to meet, that is. Never hurts to listen."
Former home secretary David Blunkett urged the party not to retreat to a "bunker", saying: "We must not revert to the far left. We must not allow ourselves to turn inwards. We must try to heal the hurt that people will be feeling."
Mr Miliband said: "This has clearly been a very disappointing and difficult night for the Labour Party.
"I want to say to all the dedicated and decent colleagues in Scotland who have lost their seats that I am deeply sorry for what has happened. And I also want to say that the next government has a huge responsibility. It has a huge responsibility in facing the very difficult task of keeping our country together.
"Whatever party we come from, if we believe in the United Kingdom we should stand up for people in every part of our United Kingdom because I believe that what unites us is much, much more than what divides us."
Among a handful of Conservative losses was employment minister Esther McVey, who lost Wirral West to Labour by 417 votes. But Conservative chief whip Michael Gove said it appeared Mr Cameron had won "a very handsome victory", giving him "considerable authority" to "go forward with a secure and stable government in the national interest".
And London mayor Boris Johnson swept back into Parliament as MP for Uxbridge and South Ruislip, saying that voters had "decisively rejected the old-fashioned and outdated policies of division" represented by Mr Miliband.
Ukip gained its first seat in a general election, but its majority in Clacton was significantly reduced from the by-election last year when Tory defector Douglas Carswell became its first elected MP. It missed out on targets in Thurrock, Castle Point and Great Grimsby, and Labour sources suggested that Ukip leader Nigel Farage might have failed in his bid to enter Parliament as MP for Thanet South
If the exit poll proves correct, it would be the first time that a ruling party has increased its tally of seats since 1983, with Conservatives increasing their strength at Westminster by 10, compared to 2010.
It would give Mr Cameron the option of attempting to form a Conservative-only minority government without having to offer ministerial posts and a role in framing legislation to coalition partners.
Although a tally of 316 is below the 326 threshold for an absolute majority, it is very close to the lower figure of 321-322 needed for all practical purposes, assuming Sinn Fein MPs do not take up their seats.
A minority Tory government might hope to get its legislation through with the support of Democratic Unionists, who are likely to win around eight or nine seats in Northern Ireland.
But Mr Cameron would face a battle to impose discipline on 30-40 right-wing Tory backbenchers on issues such as Europe and the family, where they have already established a rebellious record in the 2010 parliament.
The arithmetic could even hand the balance of power in key votes to Ukip MPs, who could be expected to use any leverage this gives them to put pressure on the Prime Minister to bring forward his planned in/out referendum on Britain's membership of the European Union, currently scheduled for 2017.
With their presence on the green benches sharply reduced from the 57 MPs they secured in 2010, the Lib Dems will have far less clout as a possible coalition partner, particularly if they are dominated by left-of-centre figures such as former president Tim Farron, a certain contender for leader if Mr Clegg steps down. The battered party may prefer to remain in opposition to lick its wounds.
High-profile Lib Dem casualties included Home Office minister Lynne Featherstone, women's minister Jo Swinson and whip Jenny Willott. Former leader Charles Kennedy left Parliament after 32 years, losing his seat of Ross, Skye and Lochaber to the SNP.