Nick Clegg's performance on Thursday's TV debate has catapulted the Liberal Democrats ahead of Labour in the polls.

A YouGov daily survey suggested the contest had become a real three-horse race, with the Lib Dems on 30 per cent to Labour's 28 per cent and the Conservatives in the lead on 33 per cent.

Mr Clegg's party took four points from the Conservatives, three from Labour and one from other parties in the poll, conducted after the historic 90-minute debate was broadcast on ITV1.

The poll is the second to show a surge of support for Lib Dems in the wake of the debate, following an ITV/ComRes survey on Friday which put the party up three points to 24 per cent, but still had trailing Labour on 28 per cent and the Tories on 35 per cent.

It indicates that the first televised leaders' debate in British General Election history may have blown the race for 10 Downing Street wide open. Not since the days of the SDP/Liberal Alliance in the 1980s have Labour been forced into third place in national polls of this kind.

The news comes after it was revealed that Gordon Brown is to subject himself to a grilling by the famously aggressive Newsnight interrogator Jeremy Paxman.

Tory leader David Cameron has yet to accept an invite to take part in a series of half-hour BBC Panorama specials with Paxman, while Mr Clegg has already done so.