John McDonnell has said the row over anti-Semitism within the Labour Party has “shaken us to our core”.

The shadow chancellor said on Wednesday the party had to fix the problem by Labour Party conference in early September. “We’ll resolve it, we’ve got to,” he said.

In the latest of a string of incidents, Jeremy Corbyn apologised today after sharing a platform with people who reportedly compared Israel to the Nazis.

The Times revealed today the Labour leader had hosted a Holocaust Memorial Day event in 2010, at which speakers are said to have likened the actions of Israel in Gaza to Hitler’s regime.

The Campaign Against Antisemitism (CAA) has referred Labour to the Equality and Human Rights Commission and made a complaint to the party about comments by Corbyn and his hosting of the 2010 event.

Labour MP John Mann said Corbyn went against “normal decency” with the 2010 meeting and said the Jewish community now believed Labour had “declared war” on it.

Stephen Kinnock, another Labour MP, tweeted: “This is now a full blown crisis for our party.”

It came as a member of Labour Party’s ruling body apologised for offensive comments about Jews.

Peter Willsman called some members of the Jewish community “Trump fanatics” and suggested they were “making up” problems about anti-Semitism in the party.

He subsequently apologised, acknowledging the “offensive nature of my comments”, and has referred himself for equalities training.

Willsman, who is standing for re-election to the National Executive Committee, said: “I recognise the offensive nature of my comments and that, in diminishing the experiences of those who face anti-Semitism in our party and society, I showed a lack of the sensitivity required for discussions around racism.”