Signs that the Liberal Democrats' new-found popularity may be fading emerged as a poll showed the party slipping back into third place.
An Ipsos Mori survey for the News of the World put the Lib Dems on just 23% - down nine points on a similar poll on Monday - behind Labour on 30% (up two) and the Conservatives on 36% (up four).
It suggests "Cleggmania" may be on the wane after both David Cameron and Gordon Brown put in much-improved performances in Thursday night's second televised leaders' debate.
But three other polls suggested the surge which followed Nick Clegg's runaway victory in the first debate is not receding completely.
A OnePoll survey for Sunday's People newspaper puts the Lib Dems neck-and-neck with the Conservatives on 32%, with Labour trailing on 23%.
The Tories were up five points on a similar poll in the paper last weekend, Lib Dems down one and Labour unchanged.
And a ComRes poll for The Independent on Sunday and Sunday Mirror shows the three-horse race for Downing Street tightening.
The Tories remain in the lead on 34% - down one point on a similar survey on Wednesday - with the Lib Dems in second place on 29% (up two) and Labour on 28% (up three).
Meanwhile, an ICM survey for the Sunday Telegraph put Tories on 35%, Lib Dems on 31% and Labour on 26%.
All of the polls suggest the country is on course for a hung Parliament on May 7.
