Labour leadership contender Ed Miliband today extended an open invitation for frustrated Liberal Democrat MPs to defect.
The shadow energy secretary said the coalition deal with the Tories was causing "widespread unhappiness" in the parliamentary party and the "welcome mat" was out for activist and senior politicians who wanted to switch sides.
His offer came after former Lib Dem leader Charles Kennedy was forced to quash persistent rumours that he was quitting the party for Labour.
The MP - who refused to endorse the alliance with the Conservatives when it was forged in May - described the speculation as "absolute rubbish".
"I am not joining the Labour Party and have not had any discussions about it with anyone from the Labour Party," he told the Sunday Mail.
"I will go out of this world feet first with my Lib Dem membership card in my pocket."
Speaking on Sky News' Sunday Live programme today, Mr Miliband said former Lib Dem voters were turning up to his meetings across the country.
"I also know that there is widespread unhappiness among Liberal Democrat MPs," he added.
"I think the idea that everyone is hunky-dory with what's going on is wrong.
"I am not going to start predicting who is going to defect and when they might do so, but I think there is a real chance for us to show that this coalition is going in the wrong direction as far as Lib Dem MPs are concerned - and as I say, the welcome mat is out.
"I think under my leadership we would have a chance of attracting people over."
Lib Dem leader and Deputy Prime Minister Nick Clegg tried to laugh off defection rumours yesterday, despite facing the anger of activists during a public question and answer session in Bristol.
"I can't do better than say what Charles has said which is that it's the silliest of the silly-season stories, it's just nonsense so I'm not going to waste any more time on it," Mr Clegg said.
"I think people want to look for cracks and divisions and tensions where they don't necessarily exist.
"Are there people who are concerned about how the coalition is operating in the Conservative Party?
"Yes, I should think so and there are in the Lib Dem party as well, that's normal.
"We're doing something very different and new but I think people in the Lib Dems know that we have entered this coalition for a five-year period and that the time to judge if it's been a success or not is not in the heat and fury of daily headlines after 100 days, it's after five years. We're governing for the long term, for the long-term benefit of the country as a whole."