More than half of Labour supporters would be more likely to vote for the party if Gordon Brown was replaced as leader, according to a new poll.
But the survey for the Sunday Express found that Labour cannot expect to revive its electoral fortunes by a change at the top.
Some 40% of voters overall questioned by ICM said they would be less likely to vote for the party if Mr Brown was replaced as leader, compared to 38% who would be more likely to back Labour.
And a clear majority (55%) thought it would be "unacceptable" for Labour to change its leader without calling a general election, compared to 39% who though it could do so.
Most popular choice to lead the Government if Mr Brown stood down was Justice Secretary Jack Straw, chosen by 24% of those quizzed, followed by Foreign Secretary David Miliband (20%), deputy leader Harriet Harman (9%) and Health Secretary Alan Johnson (5%).
Just 25% of Labour voters said they would be less likely to back the party in an election if it dumped the Prime Minister compared to the 57% who said they would be more likely to back the party if Mr Brown was replaced.
The poll gave David Cameron's Conservatives a comfortable 16-point lead, on 45% to Labour's 29%, with Liberal Democrats trailing in third on 16%.
ICM polled 1,001 adults between July 30 and August 1.
