Jeremy Corbyn said half of Labour MPs would relish seeing him fail as he made an unlikely appearance on a comedy show.
The Opposition leader was roundly ribbed as he ran the gauntlet of anarchic Channel 4 chat show The Last Leg.
He suggested Donald Trump was almost as un-presidential as a faeces-flinging monkey and insisted his reputation for being dull belied a hidden sense of humour.
In a dramatic shift from his beloved bicycle, the usually no-frills left-winger was portrayed pulling up at the studio in a white Bentley and what appeared to be a fake fur coat draped over his shoulders.
Grilled by host Adam Hills, he was asked how many of his own MPs "are watching right now hoping you'll cock it up".
"About half," he shot back - after months of rumblings in the ranks over his leadership.
Mr Corbyn dodged several quirky questions such as whether he would prefer "arms for legs or legs for arms" - quipping that Hills was "not even prepared to compromise" when he sought other options.
He also declined to be drawn on whether he would be prepared to accept a Trump presidency as a condition of getting into Number 10, insisting "that's not how it works".
But asked to say how "presidential" he found the presumptive Republican nominee on a scale of one to 10 - from "leader of the free world" to "monkey flinging his own faeces around the cage" - he shot back "around seven to nine" to gasps from the audience.
"I've got to hide it," he said of his sense of humour - citing Fawlty Towers and Jeremy Hardy - "who's a friend of mine but he starts making jokes at my expense which is embarrassing" - as his favourites.
He was grilled on an alleged snub by Tony Blair at a service for the Queen's 90th birthday, where the former Labour leader and arch critic of Mr Corbyn, was said to have passed him without a greeting.
Asked if he thought it had been deliberate, he said: "No handshake was offered by either party."
Pressed on whether he would have accepted a proffered hand, he added: "He wasn't going to offer so it's a hypothetical question."