Acclaimed historian Professor Deborah Lipstadt has compared Jeremy Corbyn’s refusal to disown Holocaust deniers with those in America who refuse to reject people who use the ‘n’ word.

In an interview to promote her new book Anti-Semitism: Here And Now, the woman who successfully took on the Holocaust-denying British historian David Irving said: “No respectable politician would associate with anyone who used the 'n' word. The same should apply to Corbyn over antisemitism.”

Professor Lipstadt – who had her epic legal battle against Mr Irving turned into the 2016 film Denial – also attacked the Labour leader’s attempt to repeatedly present himself as a life-long anti-racist who cannot be tarnished with the allegation of antisemitism.

She highlighted his references to his mother Naomi's role in the anti-fascist Cable Street riots in 1936, when Oswald Mosley's Blackshirts marched through a district of London's East End which had a large Jewish community.

“His view is 'I'm a progressive so I can't be antisemitic',” she says. “He boasts how his mother was at the Cable Street demonstration — 'I had progressive mother's milk so you can't call me antisemitic.'”

Professor Lipstadt devotes several pages in her book to analysing Mr Corbyn’s history of associating with controversial figures including Stephen Sizer, a former Church of England vicar who was accused of posting a link to an avowedly antisemitic website, and Raed Salah, a Palestinian Islamist preacher, who was invited by the Labour leader to Parliament even though he was of concern to the Home Office.

In the book, Professor Lipstadt suggests it is wrong to question whether Mr Corbyn is an antisemite himself and better to question who he chooses to associate himself with.

On Monday, the Chief Rabbi Ephraim Mirvis claimed Labour was still failing to deal with the issue of antisemitism in the Party under Mr Corbyn despite “impressive” claims they were ready to tackle the problem.