A Lib Dem minister has warned his party about forming a coalition with Labour while Ed Miliband is its leader.
Norman Lamb said he "didn't see Ed Miliband as a prime minister" - and that doing a deal with him in the event of another hung parliament could do "enormous damage" to the Lib Dems.
The public would find it hard to accept, particularly if Labour had a "low percentage of the vote", he added.
He was speaking at a fringe meeting at the Lib Dem conference in Glasgow.
"I am afraid I don't see Ed Miliband as a prime minister," he told the meeting to applause from delegates.
"And I think the idea of us being latched into a Labour government with a low percentage of the vote, led by Ed Miliband, and what's gone on in France, under Hollande, I think it could be enormously damaging for our party to be in that sort of relationship.
"It doesn't mean it shouldn't happen, if it's the right thing to do for the country, but the political implications I think are enormous, of that."
The Fabian Society/Centre Forum meeting debated the prospects for a Labour/Lib Dem coalition after next May's general election.
Mr Lamb hit back at comments by Labour frontbencher Angela Eagle, who told a similar meeting at the Labour conference that a deal would be difficult because Nick Clegg held her party in such "contempt".
"It's a bit rich for Angela Eagle to talk about venom against Labour.
"What this party has gone through, with the sanctimony from the Labour benches, just beggars belief at times."
Lib Dem party members gave this line a round of applause, but Mr Lamb was not finished.
He went on to criticise Labour's economic policy, saying: "I don't think they have yet worked out how you can be on the left at a time of economic constraint.
"Their answer, instinctively, is to spend more money."
Sometimes more money was needed, he added, such as for for the NHS.
Mr Lamb stressed that the Lib Dems were a "pluralist" party - and it would be their "responsibility" to talk to other parties if none of them managed to get an overall majority.
'Right wing agenda'
He said the Lib Dems had a "massive amount in common" with Labour on many issues and "we should be prepared to work together".
He said he agreed with Labour MP and shadow energy minister Tom Greatrex, who set out four areas where the two parties agreed with each other - "decarbonisation of the electricity supply", the Human Rights Act, regional devolution, and Europe.
If they could not work together on these issues it risked a "march towards a very right wing agenda" which would be "bad" for the country, Mr Lamb added.
Mr Greatrex was one of two Labour MPs to address the meeting - in contrast to the Fabian/Centre Forum debate at the Labour conference on the same subject which did not attract a single Lib Dem MP, despite invitations.
Ann McKechin, Labour MP for Glasgow North, was the other Labour MP at the meeting.
Both she and Mr Greatrex agreed that - if Labour didn't win a majority - they would prefer to see a looser "confidence and supply" agreement with the Lib Dems, rather than a full coalition.