Ken Livingstone has provoked fury by suggesting that Jewish people won't vote for him because they are rich, according to a letter obtained by the Jewish Chronicle.

In a letter to Ed Miliband, seen by the JC, prominent Labour supporters in the Jewish community detail their concerns about the London mayoral candidate saying they were finding it hard to support Ken, following a meeting with him.

"Ken, towards the end of the meeting, stated that he did not expect the Jewish community to vote Labour as votes for the left are inversely proportional to wealth levels, and suggested that as the Jewish community is rich, we simply wouldn't vote for him," they write.

A source who attended the meeting confirmed to the Huffington Post UK that Ken had made the comments, saying there those meeting with him gasped at Livingstone's "utter ignorance."

"He said that he couldn't get it in his head that affluent Jewish communities would vote Labour," the source said.

Adam Langleben, one of the signatories of the letter refused to comment. Neil Nerva, another signatory said: "I am disappointed. This is not a debate I wish to see publicly conducted. I'm very disappointed at the person who leaked this."

It is not known who leaked the letter however a party source suggested it was someone in Labour's own headquarters because of recent "infighting" in the party. "I'm almost certain that the leak came from Victoria Street [Labour HQ] rather than the Jewish community," they told The Huffington Post UK.

Ken's campaign had not yet released an official comment at the publication but agreed the matter was "serious."

A spokesperson for Ken Livingstone said: "This was a private meeting based on Chatham House rule, as part of Ken’s dialogue with the London Jewish community and it is our intention to respect the private nature of the meeting and continue to engage in a positive way with Jewish Londoners.

"Jewish Londoners are an important part of the fabric of London and Ken’s campaign will be seeking the votes of all Jewish voters from all backgrounds, incomes and parts of London.

"It is absolutely not the case that Ken believes Jewish people will not vote Labour – on the contrary, Jewish Londoners are an important part of the Labour vote in London and constitute many of our most important and effective campaigners. Ken’s campaign will reflect the importance of Jewish London, as will his policies and team if elected.

"Though there are bound to be different interpretations of what was discussed we view the letter in the spirit in which it was written, of wishing to continue dialogue, and making sure issues of concern to Jewish London are part of Ken's administration if elected. Ken will maintain a discussion and not allow sensationalist coverage to prevent that.

"Ken recognises there are very strong views on a number of important issues that require continued discussion, and very much wishes to continue to do so, working with the London Jewish Forum and others in that vein.

"This meeting was part of a process of engagement with Jewish London and Ken will continue that dialogue moving forward."