Vince Cable is tainted by his failure to temper Tory NHS reforms and the rise in student fees, a senior shadow cabinet member has said in stark contrast to some colleagues' apparent attempts to woo the Liberal Democrat.
Chuka Umunna launched a strongly-worded onslaught against the business secretary, whose role he shadows, accusing him of planning to oust Nick Clegg and vainly try to fool voters into thinking he was not responsible for coalition policy.
Talk of a potential Lib/Lab coalition after the next election was fuelled by shadow chancellor Ed Balls stoking coalition tensions by publicly offering to work with "sensible" people like Mr Cable on an alternative economic policy, the Press Association reported.
And Mr Cable's speech to his own party conference - in which he predicted another hung parliament in 2015 - was widely seen as holding out a branch to the Opposition.
But Labour leader Ed Miliband insisted this week that reports of discussions with leading Lib Dems were "way overdone', saying they were an "accomplice" to the Tories in government and were heading in the wrong direction.
Mr Umunna, asked about Mr Balls' comments, told a fringe meeting at the Labour conference in Manchester on Monday: "I think Ed Balls would have an issue with you describing him as adoring of Vince Cable.
"Vince does that classic thing that so many of us see Lib Dems do locally: facing both ways at once and changing your pitch whenever it suits.
"Vince says 'Plan A is absolutely right, we should go for this most austere deficit reduction strategy any western government has embarked upon at this point when the country is recovering from a downturn' but at the same time he says we have to worry about demand too, that we have a growth problem."
As a former adviser to Labour's John Smith, he said, Mr Cable would "argue he is sitting in the same space.
"But we will judge him by his actions and his actions have supported and allowed the coalition to do many things that they would otherwise not have been able to do.
"If Vince Cable had opposed the re-organisation of the NHS and said 'I do not agree with this' in cabinet they probably would not have been able to do it.
"It's the same on tuition fees - he was the architect."
Comparing Mr Cable unfavourably with Mr Clegg, he said: "I will give Clegg this bit of credit: I think he realises, and he did realise from the start, that the Liberal Democrats own everything this coalition government does.
"Vince Cable thinks that if he becomes the leader of the Liberal Democrats, and that is clearly what he wants, that somehow he is going to pose as if he doesn't have anything to do with all the things they are doing to my community.
"My community are not stupid. They won't buy that."
Labour's was "absolutely focused" on securing an overall majority, he said, and would be "grown up" in dealing with the consequences if it failed, he said.