London (BBN)-The Conservatives are on course to be the largest party with David Cameron hopeful of gaining a majority in the UK general election.
Labour faces being wiped out by the SNP in Scotland and is failing to make the gains it needs in England to stand a chance of forming a government, reports BBC.
The Lib Dems could finish with as few as 10 MPs, with Vince Cable, Ed Davey and Simon Hughes losing their seats.
The SNP could be set to gain more than 50% of the vote in Scotland.
The exit poll suggested the Tories will get 316 MPs and Labour will get 239 MPs and despite initial incredulity from Labour and the Lib Dems it so far appears to be accurate.
Speaking in Doncaster, where he retained his seat, Labour leader Ed Miliband said; "Clearly this has been a very disappointing and difficult night for the Labour Party.
"We haven't made the gains we wanted in England and Wales and in Scotland we have seen a surge of nationalism overwhelming our party."
He said the next government had a "huge responsibility" and a difficult task to "keep our country together".
Mr Cameron looks like he will be able to remain in Number 10 as the head of a minority government without the need for a coalition - although he might have to rely on the support of the DUP or the Lib Dems.
Even if Labour leader Ed Miliband was able to persuade the Lib Dems to join the SNP in backing a Labour government, he would not have the necessary numbers to get his legislative programme through Parliament in a Queen's Speech.
The finishing line needed to form an absolute majority is 326, but because Sinn Fein MPs have not taken up seats and the Speaker does not normally vote, the finishing line has, in practice, been 323.
Labour is being hammered in Scotland by the SNP, with Nicola Sturgeon's party on course to take as many as 56 of the nation's 59 seats.
Jim Murphy, leader of the Scottish Labour Party, and shadow foreign secretary Douglas Alexander have both lost their seats to the SNP, which is benefiting from a 27% average swing from Labour.
Conceding defeat, Mr Murphy said it had "proven hard to turn round years of difficulties with the Scottish Labour Party in just five short months".
He congratulated the SNP on the scale of their victory but said he intended to continue as the party's leader in Scotland.
"Scotland needs a strong Labour Party and our fightback starts tomorrow morning," he added.
The exit poll suggests the Lib Dems will lose 47 seats, taking the party back to its 1970s level of representation at Westminster.
Mr Clegg said: "It is now painfully clear this has been a cruel and punishing night for the Liberal Democrats.
"The election has profound implications for the country and for the Liberal Democrats.
"I will be seeking to make further remarks about the implications of this election - both for the country and for the party that I lead and for my position in the Liberal Democrats - when I make remarks to my colleagues in the Liberal Democrats later this morning when I return to Westminster."
Speaking at the start of the night, the Lib Dem election chief Lord Ashdown told the BBC: "If this exit poll is right I will publicly eat my hat."
Labour has failed to make the headway it wanted in the South of England and the Midlands, failing to take its top target seat, Warwickshire North, back from the Conservatives.
Its progress in London has not been as strong as pre-election polls suggested.
There is a recount in Bradford West, where George Galloway is battling Labour to retain the seat he won in a by-election.
Bradford Council has reported Mr Galloway to the police for allegedly breaking election law for tweeting about exit polls before polls closed, the BBC has learned.
This is turning into not just a bad night, not just a terrible night, but an absolute out-and-out disaster that threatens the existence of the Labour Party in Scotland.
Jim Murphy has just vowed to stay on as the Scottish Labour leader to start the "fightback". But Labour in Scotland has promised before to listen and learn after 2007 and 2011 when they lost in the Holyrood Parliament in Scotland. Could they recover?
David Cameron, arriving at his count in Witney, said it was "early days".
Conservative minster Michael Gove said: "We haven't had an incumbent government increase its majority like this since 1983 and it would be an unprecedented vote of confidence in David Cameron's leadership."
SNP leader Nicola Sturgeon has arrived at the Glasgow count at the Emirates Stadium, where she told reporters she believes it will prove a "very good night for the SNP", adding that she would like to "lock the Tories out of power".
UKIP is so far failing to win its target seats but Douglas Carswell has held Clacton for the party.
Giving her comment on the exit poll, Green Party leader Natalie Bennett said: "A doubling of MPs in Parliament would obviously be a huge advance for the Green party."
A total of 650 Westminster MPs will be elected, with about 50 million people registered to vote.
There are also more than 9,000 council seats being contested across 279 English local authorities.
Mayors will also be elected in Bedford, Copeland, Leicester, Mansfield, Middlesbrough and Torbay.
IN OTHER ELECTION DEVELOPMENTS:
Nick Clegg has held on to his Sheffield Hallam seat but said it had been a "cruel and punishing night" for his party and he would be making a statement on his future later
Scottish Labour leader Jim Murphy and shadow foreign secretary Douglas Alexander have lost their seats to the SNP
UKIP are polling strongly in the North of England and Douglas Carswell has retained his Clacton seat but Nigel Farage could fail to win South Thanet
Former Lib Dem leader Charles Kennedy lost his seat to the SNP in Ross, Skye and Lochaber
Conservative minister Esther McVey has lost Wirral West to Labour
The Green Party is predicted to get two MPs, according to the NOP/MORI exit poll for the BBC, ITV and Sky
George Galloway has been reported to the police for retweeting an exit poll before voting ended