Labour could still avoid an election defeat if it dropped Gordon Brown, according to an opinion poll.
A ComRes poll conducted for the Independent revealed that any one of eight potential replacements would help claw back at the Conservative lead in the polls.
The figures appear to confirm suggestions that David Cameron has yet to "seal the deal" with the electorate.
If Lord Mandelson, Harriet Harman, Alan Johnson, Ed Balls or Ed Miliband took over from Brown, the Conservatives would still become largest party but would be denied a Commons majority.
More worryingly for the Tory leader, the survey showed that if foreign secretary David Miliband or justice secretary Jack Straw was to take over Labour would be the largest party in a hung parliament.
If Straw were installed as leader, Labour would climb to 31 per cent, compared to 28 per cent for the Conservatives and 21 per cent for the Liberal Democrats.
And if Miliband was Labour leader, 33 per cent of those surveyed said they would choose the party, ahead of the Conservatives on 28 per cent the Lib Dems on 21 per cent.
But if Brown remains in post, the figures show the Conservative Party would take a 48-seat Commons majority.
It makes miserable reading for the prime minister, who is attempting to lead a fight-back in Brighton.
The poll also provides a significant boost for Lib Dem leader Nick Clegg.
It places his party neck-and-neck with Labour for the first time in a ComRes poll, with both parties on 23 per cent, while the Conservatives maintain their lead on 38 per cent.
The Liberal Democrats are up two points on last month, the Tories are down two, while Labour is down one point and other parties up one.
