Nick Clegg has challenged Nigel Farage to a live head-to-head debate on Britain's membership of the EU, amid Lib Dem fears the party could be wiped out in the upcoming European elections.
Speaking on his LBC radio show on Thursday morning, the deputy prime minister said he was "keen to debate Nigel Farage directly" on the future of Britain's relationship with Europe.
"I will challenge Farage to a public, open debate about whether we should be in or out of the EU," he said. “He is the leader of the party of 'out', I am the leader of the party of 'in'. It’s time for a proper public debate so that the public can listen to the arguments and decide for themselves."
Clegg said that while he disagreed with Ukip's demand that Britain should leave the EU, he said he respected the fact they had a "clear position" - unlike the Conservatives and Labour.
Farage is due to appear on LBC tomorrow morning, where he will be asked if he intends to take up the challenge laid down by Clegg.
A Ukip spokesperson said a debate was an "interesting idea" but indicated the party would only take part if David Cameron and Ed Miliband were invited.
"It would be ridiculous if Nick Clegg were to refuse to extend his invitation to David Cameron and Ed Miliband too," the spokesperson said.
“So we want to know from Mr Clegg that Mr Cameron and Mr Miliband are invited as well and that he has in mind a comprehensive and live leaders’ debate on a major broadcast outlet.
“Naturally we also want to know from David Cameron and Ed Miliband that they are not running scared and will be happy to present their case on the EU to the British public as well. We can see no reason why they would not wish to take part.
“So we need some clarity from each of the other three party leaders and hope that the media will apply pressure for such clarity in the hours ahead. In any event Nigel Farage will set out his views on this subject fully tomorrow on LBC at 9am.”
On Thursday The Times reported that Tim Farron, the president of the Lib Dems, has warned that the party faces the "fight of our lives" in May's European Parliament elections.
Voicing fears that the party could lose all of its 12 MEPs, Farron said the Lib Dem's “very presence in the European Parliament could be at stake” in a submission to the party’s spring conference next month.
In a recent interview with The Huffington Post UK, Lib Dem MP Lorely Burt said Ukip was useful for her party as it had enabled the Lib Dems to "reinforce our identity as pro-European".
Burt, a parliamentary aide to chief secretary to the Treasury Danny Alexander, said she did not think the party would lose all of its MEPs, but warned there was little chance it would gain any.
Farage has staked his future leadership of Ukip on the party performing well in May. The expectation around the party is such than anything less than first place will likely be seen as a disappointment. And Farage has admitted that if the party comes third he would likely be ousted as leader.