Nick Clegg taunted David Cameron and Ed Miliband for lacking "the guts" to take part in a televised debate on Britain's EU membership, after he and Ukip leader Nigel Farage clashed last night.
The Liberal Democrat leader said it was time for the Prime Minister to stop "dragging his feet" and confirm that he will take part in TV leaders' debates in the campaign for next year's general election.
An instant poll found that Mr Farage won last night's LBC debate, with 57% of those questioned by YouGov for The Sun saying he performed best, against 36% for the Deputy Prime Minister.
But Mr Clegg shrugged off the setback, insisting that the battle over Britain's place in Europe was "a marathon not a sprint" and that it would take time to overcome "years and years of misinformation and deeply misleading facts" spread virtually unchallenged by eurosceptics like Ukip.
Speaking on his Call Clegg show on LBC radio, the Lib Dem leader said he enjoyed his televised showdown with Mr Farage - due to go to a second round on the BBC next Wednesday - and made clear he believed the other major party leaders should be ready to debate Europe in a similar way.
"I think it, frankly, is pretty odd that both David Cameron and Ed Miliband have chosen not to debate this major issue, whether we should be in or out of the European Union," said Mr Clegg. "In the run-up to the next general election, I hope they will both find a bit more guts to step up to the plate and have a proper public debate."
Last night's exchange showed "the value of having politicians with different points of view battling it out in front of people so people can make up their own minds", said the Lib Dem leader.
In a challenge to Mr Cameron, he added: "Both Ed Miliband and I have now said that we would sign up to the way in which the leaders' debates were held at the last general election. The Conservatives are dragging their feet.
"I really don't think they should do that for much longer, because people want to have these debates, they want to hear directly from people, they want to hear the differences, they want to be able to compare and contrast."
Mr Clegg said he has not decided whether the Liberal Democrats' senior Treasury minister Danny Alexander or Business Secretary Vince Cable would represent the party in a TV debate between would-be chancellors ahead of the May 2015 election. At the last election, Mr Cable, as the party's Treasury spokesman, took on George Osborne and Alistair Darling.
Asked who would debate with Mr Osborne and Ed Balls this time round, the DPM said: "I have not yet decided and will decide that nearer the time. We are all grown-ups and we will talk about it together nearer the time."
He added: "Of course, Danny Alexander is the Liberal Democrat Treasury minister. He has presided as Chief Secretary to the Treasury over probably the biggest transformation in the public finances in a generation. At the same time, of course, Vince is an outstanding Secretary of State dealing with business issues."
Mr Cameron did not watch last night's debate live, but caught up with highlights on the 10 o'clock TV news, said his official spokesman.
The spokesman told a Westminster media briefing: "He had his weekly audience with Her Majesty the Queen at Buckingham Palace, which came to an end around the time of the start of the debate, so he will have been on his way back at that point."
Later on, Mr Cameron was "spending time with his family", said the spokesman.
Mr Farage's performance appears to have impressed News Corporation chairman Rupert Murdoch, who sent out a message on Twitter: "UKIP,Farage still making progress. Without a deal Cameron will be dead meat after 2015 elections. Prepare for Radical Labour."
Overnight ratings showed that 376,000 viewers watched the Sky News broadcast of last night's debate, which also went out live on LBC radio.
Mr Cameron said neither leader had offered "the real choice that people want" - his promise of a referendum on a reformed EU.
He said he was unlikely to "sit through the whole thing" when the second debate takes place next week.
Interviewed on Capital Radio East Midlands, he said: " I didn't watch the debate but I got the headlines.
"The problem with the debate is you had one person in Nigel Farage who can't offer a referendum to the British people and another in Nick Clegg who doesn't want to.
"So the real choice that people want to have, which is a renegotiation of our relationship with Europe, proper reform and then an in out referendum, is only offered by the Conservatives so the real choice wasn't there last night."
On BBC Radio Derby, he said: " I take part in debates every day of my life. I take part in a pretty lively debate every week at PMQs. I go on radio and TV to make the case for my policies because I think we have the best answer on Europe which is not to lamely accept the status quo which is what Nick Clegg does nor to turn your back on the world and pretend you can build a fortress Britain which Nigel Farage wants.
"I watched the headlines on the news and I've no idea what I'm doing next week but I'll probably just catch the headlines rather than sit through the whole thing."