The great undecided election

More than a quarter of voters are still undecided today, an exclusive final opinion poll reveals. In an extraordinary finish to the four-week campaign, some 27 per cent say they may change their minds as they go to the polling station.

The finding suggests that millions are torn as never before on whether to reward or rebuke Tony Blair after eight years in power. If they stick with their voting plans, the Evening Standard/Mori poll shows Mr Blair is likely to storm home to victory with a landslide majority of more than 110.

Barring a complete upset, he will enter the record books as the first Labour leader to win three in a row, all with three-figure majorities.

But such a high number of uncertain electors could make a dramatic difference to the eventual majority. It dwarfs the eight per cent who said they changed their minds on polling day in 1997.

The survey puts the parties on 38 per cent for Labour, 33 for the Conservatives and 23 for the Liberal Democrats. It is the last poll of the hard-fought election campaign.

Research continued until late last night, making the high level of indecision among the electorate even more surprising. Labour's vote share is down four points from the 42 per cent recorded in 2001 - showing the damage inflicted on the Prime Minister by the Iraq war and controversies such as student tuition fees.

The survey contains a sting in the tail for Mr Blair because more than half the electorate want him to resign within two years rather than carry on for another full term. And only one in three want Mr Blair to stay on longer than two years.

Among Labour's own supporters, a third say he should quit early. The poll suggests Mr Blair is set to win with the lowest share recorded by a winning party since 1945, with the exception of the 1974 result when Labour won with 37.1 per cent. The figures are disastrous for Michael Howard, whose controversial campaign focusing on immigration and branding Mr Blair a "liar" is bound to come under fire from Conservatives.

The Conservative share is exactly the same as it was in 2001. The party appears to be marooned on the same share as William Hague won then and is barely better than they achieved in 1997.

A failure to improve after Mr Blair was so weakened by Iraq and by searing policy rows would be seen as an even more ghastly failure by Mr Howard and his election team led by Au s t r a l i a n c a m p a i g n guru Lynton Crosby. Speculation about a Conservative leadership battle is already r u m b l i n g among Tory M P s a n d g r a n d e e s today. Conserv a t i v e s insisted they were doing better in the c r u c i a l marginals than the national polls suggest, claiming they were ahead in target seats like Finchley.

The Liberal Democrats were predicting gains in some previously safe Tory seats.

The Mori research suggests the recent slide in voter turnout will finally be turned around. It forecasts a modest increase on the 59 per cent turnout of 2001, probably helped by record levels of postal voting.

Eight in 10 voters say this election is "personally important" to them, a higher proportion than last time, which suggests the is genuine confusion about how they should make their votes count.

Liberal Democrat supporters appear to have their minds made up least of all. A third say they may change their minds while only 23 per cent of Conservatives and 28 per cent of Labour voters are not settled.

Labour was still claiming to be nervous of a shock result, mainly through the fear that its traditional supporters will not bother to vote.

Deputy Prime Minister John Prescott sent an email to thousands of activists urging them to ignore the polls. "Even though the polls show Labour in front, it doesn't mean we'll win," he wrote.

"When I was elected to Parliament in 1970, we were 16 points ahead and everyone assumed Labour had it in the bag. But we lost."

With his own leadership on the line, Mr Howard refused to give up fighting today. He spent the morning at the Conservatives' call centre in the West Midlands making personal phone calls to dozens of wavering voters.

He later travelled to his constituency of Folkestone to cast his vote.

Mr Kennedy voted this morning near his family home in Fort William, Scotland. Mr Blair returned to his Sedgefield constituency late last night after a tour of marginal constituencies.

Mr Blair's 17,713 majority is expected to be dented as a result of the challenge by anti-war protester Reg Keys, whose son was killed in Iraq.

Mori interviewed 1,628 adults by phone between 3 and 4 May.