Former business secretary Vince Cable has branded Jeremy Corbyn an "ageing lion" being hunted by the Tories.
The Liberal Democrat, who lost his seat in May, said Labour's new leader was "completely unelectable" and the Conservatives "will slaughter them".
He told a fringe meeting at the Lib Dem conference in Bournemouth: "Of course the Tories are just waiting with their big bore guns and there's this ageing lion and they're just waiting to open fire."
The analogy sparked memories among the audience of Cecil, a 13-year-old male lion who was killed in Zimbabwe by American dentist Walter Palmer in July.
Cable said Corbyn and his shadow chancellor, John McDonnell, were "perfectly agreeable as individuals". But he added: "They are not electable – they're just not.
"You just look at their core economic ideas, all the things they said in the past and now they're trying to disown – the Tories will slaughter them. The Tories are absolutely ruthless, as we know to our cost, and they will slaughter them."
Cable claimed that Labour had been engulfed in an "enormous civil war" since Corbyn, a left-winger who had sat on the back benches for over 30 years, was elected last week.
He said there was a possibility that some Labour MPs could defect and there could even be "a mass exodus at some point, with new political formations being created".
But Cable added: "I think they're more likely to stay put and I think therein disaster lies. Because what will happen is that the more moderate people in the Labour party will persuade Corbyn to change his views on a few issues – you've seen this already with Europe – and then of course they'd be stuck with him."
He said there was both an "opportunity and responsibility" for the Lib Dems because the "country desperately needs an elected opposition".
Last week Lib Dem leader Tim Farron dismissed the possibility of defections from Labour in an interview with BuzzFeed News but opened his arms to Labour supporters worried about Corbyn's leadership.