Ukip's extraordinary surge in the polls appears to have faltered, after a new poll saw them lose a third of their support and fall back to level with the Liberal Democrats.
The ICM poll for the Guardian put the party on 12%, down from 18% - although that is still three points above its previous high.
Labour won two more points to find itself on 36%, while the Tories gained one point to end up on 29%.
The Lib Dems rose one per cent to win 12% support.
"With voters plainly fed up with politicians of all stripes, it seems that fewer are ready to admit – perhaps even to themselves – who they will plump for next time," ICM director Martin Boon said.
"That leaves us with more adjusting to do than normal."
David Cameron and George Osborne are still the most trusted people to run the economy, despite Ed Miliband and Ed Balls' efforts last week to win back some economic credibility with the public.
The Cameron-Osborne team have a nine-point lead on economic trust.
But less than half the respondents believe Cameron has the backing of his own party, compared to 62% last year.