Jeremy Corbyn has made a renewed effort to outline his opposition to antisemitism.

Speaking at a May Day rally in central London, Mr Corbyn said Labour stood “absolutely” against Jew-hatred in any form.

His comments came as the months-long row over antisemitism allegations in the party reached new heights in recent days.

Mr Corbyn told the event – attended by thousands of people ahead of a march to mark an international day honouring workers – that Labour stood in solidarity against the growth of far-right activism across Europe.

He went on to say: “We stand absolutely against antisemitism in any form.

“We stand absolutely against racism in any form. We stand united as a Labour movement, recognising our faith diversity, our ethnic diversity.

“And from that diversity comes our strength. That is the strength of our movement.”

Earlier, Mark Regev, Israel’s ambassador to Britain, said the crisis engulfing Labour had “crossed a red line” . Modern antisemites were targeting “the collective Jew”, he said.

Mr Regev said: “The comments of the past few weeks are demonising, a vilification of my country and its very right to exist. There’s a difference between legitimate criticism and hate speech. Hating Jews is a red line that cannot be crossed.”

In a statement issued today, The Board of Deputies said it welcomed news of Labour's independent inquiry into antisemitism.

"The inquiry must be rigorous and fair in order to ensure that it has credibility," a spokesman said.

"We will work with the party to seek to ensure that the inquiry fairly addresses the problems on which the events of the past few weeks have shone a spotlight.

"We are astonished and appalled at Ken Livingstone's unrepentant attitude. It would be inconceivable for an anti-racist party to allow him back in.

"The Board of Deputies has been shocked and dismayed at the many people who seem to be in denial of the problem of antisemitism which is so clear.

"At the same time, we wish to recognise the many leading Labour politicians and activists from all sections of the party who have spoken out against antisemitism in all its forms and to express concern at the intimidation to which some of them have been subjected."

The Board said it hoped the inquiry would mark the start of a "more certain and clear Labour attitude against antisemitism, from the leader to the grassroots".