The Green Party has said it will “reach out” to an antisemitism watchdog to better understand Jew-hate, after footage emerged of one of its leadership candidates giving an vehemently anti-Israel speech.

In 2009, during Israel’s Operation Cast Lead, Shahrar Ali delivered a speech in which he compared the Holocaust and Israel’s offensive on Gaza.

Video of the speech resurfaced as Mr Ali is now one of three candidates for the leadership of the Green Party of England and Wales, alongside Leslie Rowe and a joint candidacy of Jonathan Bartley and Sian Berry.

In the speech, Mr Ali says: “Just because you observe the niceties of Holocaust Memorial Day, does not mean that you have learned the lessons of history.

“Listen up warmongers…just because you switch off your TV set to avoid upsetting your children, does not mean that you have not killed our children.”

The Green Party said it was “informally” alerted to the footage previously in 2009 but said its process of dealing with it at the time was “inadequate”.

A party spokesperson said on Tuesday: “Tackling antisemitism, Islamophobia and all forms of racism wherever they exist and by whomever they are perpetrated is core to the Green Party’s aims.

“In 2016 our processes were updated and refined to ensure that such instances would be dealt with quickly and fairly. We are in on-going discussions about how to further improve these processes.

“Having been contacted about this today, we believe it is absolutely critical that we discuss it openly and quickly, and we are doing so.”

The party added that it had “reached out” to the Campaign Against Antisemitism group to “ensure we fully understand their concerns and to respond accordingly.”