Documents published by Wikileaks reveal that Clinton claimed Labour party members were so furious at being “shafted” by Tony Blair that “they went out and practically got a guy off the street” instead.
The explosive remarks, to a private dinner of wealthy donors in October 2015, show the former President comparing Corbyn to leaders of anti-austerity parties like Greece’s Syriza.
The documents – part of a raft of leaks designed to undermine Hillary Clinton’s Presidential bid – reveal that he also attacked Ed Miliband for being too left wing for British voters.
Transcripts of his speech, contained in newly leaked emails, show Clinton saying:
“If you look all over the world – the British Labour Party disposed of its most [inaudible] leader, David Miliband, because they were mad at him for being part of Tony Blair’s government in the Iraq War.
“And they moved to the left and put his brother in as leader because the British labour movement wanted it.
“When David Cameron thumped him in the election, they reached the interesting conclusion that they lost because they hadn’t moved far left enough.
“And so they went out and practically got a guy off the street to be the leader of the British Labour Party, who I saw in the press today said that he was really a British citizen and had real British [inaudible]. “
“But what that is reflective of – the same thing happened in the Greek election – when people feel they’ve been shafted and they don’t expect anything to happen anyway, they just want the maddest person in the room to represent them.”
A senior Labour source told HuffPost UK that by ‘maddest’, Clinton had meant ‘angriest’, rather than ‘craziest’.
“Bill Clinton was clearly using the American term of mad - as in angry - in his comments about Jeremy,” the source said.
“A lot of people felt angry about UK politics at that time just before Jeremy was elected.”
The Corbyn section of Clinton’s remarks, which emerged in an email sent by aide Varun Anand, were part of his wider argument that the ‘winner of any election is determined by what people think the election is about’.
Clinton said that in her battle with Bernie Sanders, his wife Hillary had been trying to appeal to all of the ‘struggling, the striving and the successful’ while her opponent said ‘just go get the money from the millionaires’.
He admitted that “it sounds good” to have the angriest message, and pointed to the way Labour had shifted from Blair to progressively more leftwing leaders.
When contacted by HuffPost UK, Corbyn’s office refused to comment on the remarks.
Corbyn has in the past voiced his support for Bernie Sanders, and claimed that he had helped shift Hillary leftwards on issues such as free trade.
Corbyn claimed at one rally this summer that Sanders had sent him a message of support in his battle against Owen Smith for the Labour leadership.
But his office had to withdraw the claim after Sanders stressed he didn’t want to interfere in the race.
The Labour leader has also on record as a defender of Wikileaks and its founder Julian Assange.
The Democrats have repeatedly claimed that Wikileaks data dumps are part of a Russian cyber strategy that has hacked into its party material.
WikiLeaks is one of the most high profile sites that has been posting thacked Democratic Party materials. The organisation has however denied any connection with the Russian authorities.
Lib Dem leader Tim Farron said: “The idea that Bill Clinton thinks that Jeremy Corbyn is useless should come as no surprise to anybody. But it shows you how far into the wilderness Labour have gone. Labour are the most irrelevant the party has ever been.”