LONDON - As UK polling booths closed, Gordon Brown, David Cameron and Nick Clegg could do no more than anxiously await the results that will determine their own and the country's future.
There was cautious optimism among the Conservatives that Mr Cameron would become Prime Minister - and rising hopes that they would win an overall majority by crossing the crucial finishing line of 326 seats. "It's in sight but we can't be sure it will be reached," said a senior Tory source.
There was gloom in Labour circles and some cabinet ministers said farewell to their Whitehall departmental staff on Thursday, in a sign that they expected to be out of office.
The final poll of the campaign showed the Tories seven points ahead but still short of an overall majority. The Ipsos Mori survey for the London Evening Standard put the Tories on 36 per cent, Labour 29 per cent and the Liberal Democrats on 27 per cent. Sir Robert Worcester, the founder of MORI, said: "We are looking at a 'hung-up' parliament where Cameron may get his Queen's Speech and Budget but the question will always be, how long can he carry on?"
After one of the most dramatic campaigns in modern times, even the best brains in the three parties admitted they could not be sure of the result.
"Too close to call" is one of the oldest cliches in the political lexicon but it still applied to this contest as the final votes were cast.
There were signs of a high turnout in which two out of three of the record 44 million people registered to vote had done so - which would be higher than the 61 per cent figure in 2005 and 59 per cent seen in 2001.
Half a million people have registered to vote since April 1 and there was a surge, including many young people, after the first of the three live party leaders' television debates, for which the 2010 election will most be remembered.
The debates electrified the campaign and - for a while, at least - propelled a much-criticised two-and-a-half party system into a new era of three-party politics. Only the actual results will tell us whether the surprise momentum for Mr Clegg's Liberal Democrats would translate into more bottoms on seats in the new House of Commons that assembles on 25 May for the Queen's Speech.
Although Mr Clegg will not be Prime Minister, the anxiety level in the Liberal Democrats is arguably even higher than in the two old parties. The third force has seen many false dawns, not least in 1983, when the SDP-Liberal Alliance came desperately close to overtaking Labour and coming second. In the event, Labour hung on to second place n as it hopes to do again this time n and the split anti-Tory vote delivered Margaret Thatcher a thumping majority of 144.
In the euphoria after the first TV debate, it seemed Mr Clegg's target to double his 63 MPs by the election after this one was well in his sights. But his party's surge in the polls was not maintained and some analysts said it had peaked too soon - a nice problem for the Liberal Democrats to have, but a problem nonetheless.
According to Ipsos MORI, some 12 per cent of people said they may vote tactically. On the face of it, this will raise the hopes of cabinet ministers such as Peter Hain and Ed Balls, who hinted that Labour and Liberal Democrat supporters should vote for the candidate most likely to defeat the Tories in their constituency.
Yet Labour refused to endorse that approach officially and some of its strategists believe that urging tactical voting is a double-edged sword because some people would be tempted to vote to oust Mr Brown, whose own ratings trail those of his party.
Staff at some polling stations reported the busiest start to a general election polling day they could remember. "It has been very brisk," one said. Another said people were "flooding in" as soon as voting opened at 7am.
The vast majority of constituencies were due to begin counting at 10pm local time (9am Friday NZT), with about 20 - including some marginal seats - not due to start the process until 9am Friday UK time (8pm Friday NZT).
Some of the 4,150 candidates face a long wait. Delays in counting were expected in seats where there was a high number of postal votes and the 164 areas in England where local elections took place, including the 32 London boroughs, 36 metropolitan authorities and 20 unitary authorities. In these elections, a total of 15,785 candidates are contesting 4,222 seats. Voters will also choose their mayors in Hackney, Newham, Lewisham and Watford.
Boris Johnson, the Tory Mayor of London, predicted an "enormous" turnout as he cast his vote at a polling station in Islington, north London. "I think this has been a transformatory election campaign. I think people have been more enthused and more interested than by any one I can remember," he said.