Britain is likely to face a second election shortly after May 7 because of a knife-edge outcome, political experts have warned. The likelihood of another coalition lasting five years has been dismissed as miniscule by a leading academic. A second election swiftly after polling day is 'extremely likely', Professor Paul Whiteley of the University of Essex said. Britain is likely to face a second election shortly after May 7 because of a knife-edge outcome, political experts have warned . 'I don't see another coalition government lasting five years,' he said at a briefing by polling experts on the latest election forecasts. Other experts also warned that a 'messy and unstable' left-wing alliance was likely to be in power even if the Conservatives won more seats or a greater share of the vote. Mr Whiteley predicted a repeat of the disastrous Left-wing Lib-Lib pact of the 1970s. It ended with Labour Prime Minister James Callaghan losing a vote of no confidence. 'That was not very successful. It had to go to the IMF for a bail out and there were huge industrial problems.' The disastrous pact led to the rise of Margaret Thatcher and the Tories held on to power for another 18 years. Experts said the likeliest outcome at the general election would be the Conservatives winning the most votes, but a left-wing alliance forming to keep them out of power. Oxford academic Stephen Fisher said there was a high chance Labour would form either a minority government or coalition with the help of the SNP, Liberal Democrats, Greens or other minor parties. There was 'only a 42 per cent chance of a Conservative-led government, even though there is a two-thirds chance of the Tories being the largest party, on votes or seats.' He added: 'The single most likely outcome is…a seriously hung parliament with the Conservatives as clearly the largest party but a majority on the left, including the SNP and Liberal Democrats.' David Cameron answers questions from 02 employees  in Leeds this afternoon ahead tonight's 'Challengers' television debate . Labour leader Ed Miliband addresses supporters during a visit to Crouch End  in north London this morning . This would be a 'messy and unstable situation' and it was 'not clear that this diverse group of parties would be able to sustain a stable government'. The Conservatives would probably turn to the DUP first and then the Lib Dems to try and form a government but they were still likely to be short of a majority, he added. The SNP's surge in Scotland was likely to be hugely damaging for Labour but Ed Miliband could still walk into Number 10 propped up by an alliance of left-leaning parties. A massive landslide to the SNP was inevitable, with the party winning at worst six times more seats than it currently holds or at best nine times more. Labour's disastrous performance in the Scottish polls could mean the party only has one safe seat: the Glasgow seat of Willie Bain. John Curtice, professor of politics at Strathclyde University, said the SNP vote surge was nothing new. Some 45 per cent of Scots had voted for the SNP in the 2011 Scottish parliamentary elections, 45 per cent voted in favour of independence during last year's Scottish referendum and the polls were now showing 45 per cent supported the SNP. But for the first time Scottish voters were voting the same way at a Westminster election as they would for the Scottish parliament.
Second election after polling day is 'extremely likely', academics claim . Professor Paul Whiteley of Essex University predicts left wing coalition . But he said: 'I don't see another coalition government lasting five years' Tories will finish largest party but without enough allies to form a coalition .