As Clegg's popularity grows, so his demands begin to spook rivals

At the start of the campaign, the Liberal Democrat leader was treated with deference. Not any more, reports Andrew Grice

Labour and Conservative attacks on the Liberal Democrats have failed to burst Nick Clegg’s bubble and his party is now just one point behind the Tories in a remarkably close three-way race.

The latest ComRes survey for The Independent and ITV News puts the Tories on 32 per cent (down two points since the weekend), the Liberal Democrats on 31 per cent (up two), Labour on 28 per cent (unchanged) and others on nine per cent (unchanged). It is the Liberal Democrats’ highest rating since ComRes began polling in 2004.

The figures would make Labour the largest party in a hung parliament with 268 MPs even though it is third in the share of the vote. The Tories would win 238 seats and the Liberal Democrats 112, leaving Labour 58 seats short of an overall majority.

More than one in five people who voted Labour at the last election (21 per cent) have switched to Mr Clegg’s party, as has almost one in 10 Tory supporters (eight per cent).

Yesterday there were signs of panic in the high command of both the Labour and Tories at the apparently unstoppable Clegg bandwagon, which has turned next week's election into the most unpredictable for decades. Both parties spent the day directing their fire at the Liberal Democrats. The Tories warned that a vote for Mr Clegg would leave Mr Brown in Downing Street, while Labour claimed it would allow David Cameron to win power.

The dramatic poll points to a photo-finish in the election race – and that, so far, the concerted attacks by what Mr Clegg calls the “two old parties” is failing to impress the voters.

Despite that, ComRes found that only one in five (20 per cent) of voters would prefer a hung parliament, while 72 per cent would like one party to win a clear majority. Among those who want to see a majority government, 37 per cent want a Tory one, 29 per cent a Labour administration and 22 per cent one formed by another party.

By a margin of two to one, those who want to see a hung parliament favour a Lib-Lab deal rather than a Lib-Con agreement.Fifty-six per cent would prefer a Labour government with the support of the Lib Dems, while 27 per cent would like to see a Tory administration with the support of Mr Clegg’s party. Of those favouring a hung parliament, 32 per cent intend to vote Liberal Democrat, 16 per cent Labour, nine per cent Tory and 20 per cent are “don’t knows” or declined to say.

ComRes also asked people to name their second preference to test the possible impact of Labour’s plan to bring in the Australian-style alternative vote (AV) system, under which people rank candidates in order of preference. Some 68 per cent of Labour supporters, and 41 per cent of Tories, would give a second preference vote to the Lib Dems. Analysis by John Curtice, professor of politics at Strathclyde University, found that the Lib Dems would win twice as many seats under AV than the current first-past-the-post system, the Tories would come a poor third and Labour would still be the largest party.

According to ComRes, there are signs of a higher turnout than the 61 per cent who voted in 2005. Some 69 per cent say they are “absolutely certain to vote” this time, including 81 per cent of those 65 and over and 42 per cent of 18-24 year-olds. About 3.3m of these people are still undecided.

Mr Clegg again dominated the campaign yesterday as the other parties struggled to cope with the unexpected three-way contest. He said he would be prepared to work with a “man from the moon” to deliver his objectives – but not Gordon Brown if Labour finished third in the share of the vote. He said: “I think, if Labour do come third in terms of the number of votes cast, then people would find it inexplicable that Gordon Brown himself could carry on as prime minister which is what the old convention would dictate.”

Douglas Alexander, Labour’s campaign co-ordinator, replied: “My sense is that Nick Clegg has somewhat overreached himself – maybe intoxicated by the publicity he has received – in getting into the prediction business.”

Mr Cameron accused Mr Clegg of “holding the country to ransom” to benefit the Liberal Democrats, saying he was “interested in one thing and that is changing our electoral system so that we have a permanent hung parliament, we have a permanent coalition, we never have strong and decisive government.”

The Tory leader did not entirely close the door to electoral reform in the event of a hung parliament but backed first-past-the-post. He said: "I think it is a decisive way of changing our government... I do not want the electoral system changed."

The Tories warned a hung parliament could "paralyse" Britain, unveiling a mock TV election broadcast from "The Hung Parliament Party" promising to bring the economy to its knees and send interest rates soaring.George Osborne, the shadow Chancellor, said: "Only a Conservative majority guarantees change for the better. Only a Conservative majority can secure the recovery."

ComRes telephoned a random sample of 1003 GB adults on 24-25 April 2010. Data were weighted to be representative of all adults and by past vote recall. ComRes is a member of the British Polling Council and abides by its rules. Full tables at www.comres.co.uk .