Prime Minister David Cameron must not use the UK Independence Party as an excuse to dodge televised debates between political leaders at the next general election, Nick Clegg has warned.
The Deputy Prime Minister said ensuring the three main Westminster leaders go head to head again is top priority but paved the way for Ukip's Nigel Farage to be involved, telling reporters he would "relish" taking him on.
Mr Cameron has made clear he does not believe Ukip should be represented if agreement is reached to repeat 2010's groundbreaking TV showdowns.
Senior Liberal Democrat sources did not dismiss suggestions that the PM would be a "chicken" if he "wriggled out" out of the prime-time discussions.
At a press conference in Westminster, Mr Clegg said: " I'm ready to sign up now as leader of the Liberal Democrats to the same format of those broadcast leaders debates as happened last time.
"I think we had success, I think people liked them, I think they were a step forward, people felt they could compare and contrast the political leaders and I think it's really good news the Labour party appear to be prepared to do the same.
"So the only major party leader of a major party represented in the House of Commons who still needs to, if you like, sign along the dotted line is David Cameron and the Conservatives.
"I hope they won't use their anxieties about Ukip and Nigel Farage as an excuse not to give the British people the right to see those leaders' debates take place again next time.
"I think it would be a real step backwards if any party leader were to use an excuse not to do these leaders' debates again.
"The key thing is to get agreement from the three party leaders of the three main parties represented in the House of Commons.
"Then you can have a debate... I personally have got no problem at all debating with Nigel Farage, I would probably relish it actually, but the first thing you have got to do is get Labour, Liberal Democrat and Conservative party leaders to agree to do this again.
"I'm prepared to do it, I understand Ed Miliband is, I hope David Cameron will as well."
Mr Farage has threatened to broadcast a rival show to voters if Ukip is excluded from official debates but Mr Cameron has previously insisted any format ''predominantly should be about people who have a prospect of becoming prime minister''.