Jeremy Corbyn was asked to show his party “isn’t just for the many but not the Jew” by a businesswoman in the audience as he addressed the CBI Conference on Monday.
The Labour leader was forced to respond to a question from Hannah Kaufman, who is Jewish, from the Patchwork Foundation, who said: "All the speakers today have been talking about the importance of diversity in business and politics.
“But a recent survey showed that 85 percent of British Jews in the UK think that you yourself are personally antisemitic.”
The crowd applauded as she concluded: “I wanted to ask, what are you going to be doing personally to demonstrate you care about racism and antisemitism in society, and show that Labour isn’t just for the many but not the Jew?”
The Labour leader replied saying antisemitism has "no place whatsoever in a civilised society" but then widened his answer to discuss other forms of racism, including Islamophobia.
He said: "I've spent my life opposing racism in any form, be it done by the far-right or by the random attacks on individuals, or against a man that was murdered outside my house because he happened to be a Muslim and there happened to be a racist person driving a vehicle that thought it was OK to drive in a crowd of worshippers.
"Just as much as those people that attack synagogues, daub fascist graffiti over them, or attack Jewish people in this country, the USA or anywhere else, have no place whatsoever in a civilised society."
He added: "The history of the Jewish people has been one of the most unbelievable and egregious - (with) attacks on them in central Europe throughout the early part of the 20th century, which of course ended with the Holocaust and all the horrors that went with that."
On Monday, video also emerged showing Mr Corbyn sharing a platform with and warmly greeting a pro-Palestinian activiss who described Jews as “immoral”.
The Labour leader was to the stage at a rally in London in 2008 as Ishmail Patel chairman, of the Friends of Al-Asqa group, spoke just feet away.
Mr Patel has previously praised Hamas for "standing up to Israel" and insisted it is "no terrorist organisation".
As Mr Corbyn looked on he tore into Jews over the situation in the Middle East, saying: "We see the impact of Zionism on Palestinians.
"But it has had a devastating effect on the Jewish community itself: it has made them immoral in justice."
He also said: "How can you have a community that celebrates the killing of innocent Palestinian people? This is what Zionism has done to Judaic faith."
As he leaves the stage, Mr Corbyn pats him on the back.
The footage was obtained by the Red Roar website and was filmed at a Palestine Solidarity Campaign event. Mr Corbyn was a long-term patron of the organisation.