Vince Cable has publicly condemned long-time ally Matthew Oakeshott for funding the private polling which further undermined Nick Clegg earlier.
The business secretary, who yesterday issued a statement backing up Clegg while on a trade visit to China, again found himself obliged to release another clarification singling out Oakeshott for the leaked polling figures.
It followed an afternoon of finger-pointing in which allies of the embattled Lib Dem leader accused Oakeshott of being responsible for data leaked to the Guardian newspaper suggesting Clegg was on track to lose his Sheffield Hallam seat.
"Lord Oakeshott's actions are totally inexcusable and unacceptable," Cable said, confirming Oakeshott's identity as the man behind the polling for the first time.
"I have made it very clear repeatedly that he does not speak or act for me.
"Commissioning and publishing polls without the consent of the member of parliament, as in the case of Sheffield Hallam, is utterly reprehensible."
The Liberal Democrats remain deeply divided about the best course for the party's future, however. One poll of grassroots activists by the website LibDemVoice found 39% of respondents want Clegg to resign, compared to 54% who want him to remain in place.
"Among those who want Nick Clegg to stand down opinion is divided as to what should happen next," co-editor Stephen Tall said.
"And the MP who tops our poll as the next leader if there were a vacancy – current party president Tim Farron – has already pledged his loyalty to Nick Clegg. Without a rallying point, it's hard to know where the rebellion against Clegg can go next."
Another liberal commentator, Benjamin Ramm, predicted that Cable would wait until after the 2015 general election before making a move on the leadership.
"Cable remains popular both in the parliamentary party and among activists, and would be the ideal leader to enter coalition with Labour, which would be the preference of most party members," he said.
"But the window for action is rapidly closing: MPs will risk upheaval only if they see a distinct, bold alternative, ready to move swiftly."
Cable himself has made clear he does not want to move against the deputy prime minister.
"There are undoubtedly raw feelings in the wake of poor local and European election results," he added.
"We need to respond in a measured way. Public speculation about the leadership is an unwelcome distraction and as I made absolutely clear yesterday there is no leadership issue as far as I'm concerned."
Speculation over Clegg's future has peaked after a disastrous set of elections for the Lib Dems, which lost all but one of their 11 MEPs.