Jeremy Corbyn refuses to apologise four times to the Jewish community after the Chief Rabbi accused him of being "unfit" to be PM.
He was grilled on his handling of the crisis after Ephraim Mirvis warned the “overwhelming majority” of British Jews are “gripped by anxiety” over the outcome of the election.
In a dramatic article, he condemned what he called the “utterly inadequate” response of the Labour leadership to anti-Semitism cases and the departure of Jewish MPs and staff from the party.
In an interview with the BBC's Andrew Neil, the Labour leader was challenged over Rabbi Mirvis's allegation that Labour's claims it is doing everything to tackle anti-Jewish racism was a "mendacious fiction".
"No, he's not right. Because he would have to produce the evidence to say that's mendacious," Mr Corbyn replied.
He insisted he has "developed a much stronger process" and had sanctioned and removed members who have been anti-Semitic.
Mr Corbyn also denied that the blight increased after he took over the party, saying: "It didn't rise after I became leader.
"Anti-Semitism is there in society, there are a very, very small number of people in the Labour Party that have been sanctioned as a result about their anti-Semitic behaviour."
But he repeatedly refused to apologise when asked by Mr Neil.
"We will not allow anti-Semitism in any form in our society because it is poisonous and divisive, just as much as Islamophobia or far-right racism is," Mr Corbyn said.
Mr Corbyn insisted he had "strengthened the processes" since a written warning was given to a member who questioned the murder toll of the Holocaust.
Rabbi Mirvis wrote in The Times that Labour's handling of the issue that has dogged the party under Mr Corbyn's leadership was "incompatible" with British values.
He said the overwhelming majority of Britain's Jews were "gripped with anxiety" ahead of the General Election on December 12, warning "the very soul of our nation is at stake".
Mr Corbyn said of the Chief Rabbi: "I'm looking forward to having a discussion with him because I want to hear why he would say such a thing."
In a speech at an event to launch Labour's Race and Faith manifesto in Tottenham, north London, Mr Corbyn made no direct mention of the comments by the Chief Rabbi - until he was pressed by the media.
Mr Corbyn insisted when Labour activists have committed antisemitic acts they are “brought to book and if necessary expelled from the party or suspended or asked to be educated better about it”.
He added: “I ask those that think things have not been done correctly to tell me about it, talk to me about it, but, above all, engage."
But in devastating remarks, Labour peer Lord Falconer blamed a “failure of leadership” for the fact there were still at least 130 outstanding serious cases.
He said: “We deserved an attack that strong, we need to deal with anti-Semitism properly. We are not dealing with the cases within the party."
The Archbishop of Canterbury backed the Chief Rabbi, highlighting the “deep sense of insecurity and fear felt by many British Jews” and calling for words to be accompanied by "visible action" against anti semitism.
In a statement, the Muslim Council of Britain said: “Racism wherever it comes from - whether from the left or the right - is unacceptable and not enough is being done.
"We agree with the Chief Rabbi’s observation that ‘some politicians have shown courage but too many have sat silent’.
