LONDON, May 7 (AFP): Britain's opposition Conservatives came top in knife-edge elections on Thursday but without a clear-cut majority to return to power after 13 years in opposition, exit polls suggested.
The Conservatives were set to win 307 seats -- short of the 326 seats for an absolute majority in the 650-seat House of Commons -- against 255 for Prime Minister Gordon Brown's Labour Party and 59 for the Liberal Democrats.
In a so-called "hung parliament," the Lib Dems, Britain's traditional third party, could emerge as kingmakers in a power-sharing deal after their spectacular surge during a grueling month-long campaign.
The exit polls were released as polling stations closed at 10:00 pm (2100 GMT). Early results could start coming in as soon as an hour later, but the bulk is expected to be declared from around 3:00 am.
The final result may not be known until much later if it hangs on a handful of seats, as some two dozen constituencies are not expected to be declared before noon on Friday.
The exit poll forecasts were in line with several eve-of-election polls which had suggested the Conservatives had a clear lead over Brown's ruling Labour Party and Nick Clegg's Liberal Democrats.
But they indicated that Britain could be set for a hung parliament for the first time since 1974.
The result could spark a scramble for power, with Cameron seeking a partner to govern or doing so through a minority government, possibly with the support of a handful of lawmakers from Northern Ireland.
More than 44 million voters were eligible to cast ballots, with observers predicting turnout could be as high as 70 percent after an unusual campaign transformed by the first televised leaders' debates in a British election.
Exit polls have a mixed track record of accurately predicting the outcome of British general elections in recent years.
Forecasts in 1992, the last really close-fought race, were a long way out but in the last general election in 2005, they proved correct.
Election day itself had been marked by a plane crash which injured a high-profile anti-Europe candidate and a protest outside the polling station where Cameron voted.
Cameron and his wife Samantha voted first of the three main leaders in the picturesque village of Spelsbury in his Witney constituency in Oxfordshire, west of London.
Brown, who has been fighting for his political life in a frantic week of campaigning, was accompanied by his wife Sarah as he voted in steady drizzle in his constituency in Fife, north of Edinburgh.
Clegg cast his ballot in Sheffield, northern England, where he was elected for the first time in 2005.
Clegg, who catapulted his party into second place for a time during the campaign with his TV performance, had pleaded with voters to the last to back him and seize a "once in a generation opportunity to do things differently".
Nigel Farage, a high-profile candidate for the eurosceptic UK Independence Party (UKIP), suffered minor head injuries and needed heart tests after the light aircraft he was travelling in crashed at an airfield in Northamptonshire.
Brown, who took over from Tony Blair in 2007, had ended his campaign in his native Scotland, issuing a last-ditch plea to wavering voters to back Labour as the best party to safeguard the country's fragile recovery from deep recession.
"At this moment of risk to our economy, at this moment of decision for our country, I ask you to come home to Labour," he said.
Late Thursday, one Labour candidate who embarrassed Brown on the eve of the election by branding him Britain's "worst prime minister" said he would not bother to go the election count later Thursday night.
"I had no chance of winning anyway, but I've been disowned by the party... I've decided not to go to the count -- I'll stay at home and watch the BBC," he said.