Detectives for London’s Metropolitan Police are searching for a masked extremist who was filmed calling for Jewish “blood” during an anti-Israel protest last weekend.

In footage shared on social media, the youth was filmed telling a group of protesters: “We’ll find some Jews here … We want the Zionists, we want their blood!”

In the video, two police officers are seen walking alongside the masked man, yet they appeared to do nothing to challenge the extremist.

In a statement given to The Times, Scotland Yard said: “The Met is aware of a number of clips on social media capturing antisemitic or offensive remarks during demonstrations across London on Saturday, May 22, and Sunday, May 23.”

“Detectives from the Met’s public order crime team are making a number of inquiries as part of a post-incident investigation.

“Anyone with information on these clips is asked to contact the Met by dialing 101 or tweeting @MetCC on Twitter. The Met will never tolerate hate crime and this behaviour has no place in our city. All our communities should be able to live their lives without harassment or abuse.”

During the protests last weekend, pro-Palestinian activists were heard shouting “Israel is a terrorist state”,  waved placards comparing the Jewish nation to Nazi Germany, burned the Israeli flag, and attacked a car.

The rally on Saturday was joined by far-left MPs including former leader Jeremy Corbyn, John McDonnell, Zarah Sultana, and Claudia Webbe, all of whom gave speeches in Hyde Park to a crowd of pro-Palestine protesters.

The week prior, another large-scale protest was held against Israel in London. Radical socialist Jeremy Corbyn — who was suspended from the Labour Party over failures to take on anti-Semitism within his own party — also attended the rally, calling for the United States and the UK to cease military cooperation with Israel and for Britain to recognise Palestine as a state.

The demonstration devolved into chaos as activists chanted “Allahu Akbar” while pelting police officers with makeshift missiles and wooden sticks.

On Sunday, Communities Secretary Robert Jenrick warned that the rise of anti-Semitism in Britain is likely linked to radical Islamist elements within Britain.

Jenrick said that the government needs to be “alive” to the threat of radical Islam “because some of the themes we’ve seen in recent weeks are more than just casual anti-Semitism, or people who don’t understand what anti-Semitism is, and drift into it by accident.”

He pointed to an incident earlier this month, in which a pro-Palestinian car protest was filmed in London, with members of the motorcade yelling: “F*** the Jews”, “F*** their mothers”, “F*** their daughters”, and “Rape their daughters”.

Follow Kurt Zindulka on Twitter here @KurtZindulka