While the majority of arrests were for supporting a proscribed group – an offence under the Terrorism Act – there were a significant number of other arrests made after the protest turned violent for assaults on police officers and other public order offences, read a statement issued by the Metropolitan Police.

In total, 857 people were arrested under Section 13 of the Terrorism Act 2000 (TACT) for showing support for Palestine Action and 33 people were arrested for other offences, including 17 for assaults on police officers.

"In line with the policing plan put in place ahead of the operation, all those arrested were processed at a prisoner reception point in the Westminster area," police said.

Police said all 857 individuals arrested for Terrorism Act Offences will now be investigated by the Met’s Counter Terrorism Command.

Deputy Assistant Commissioner Claire Smart who led the policing operation said: "I’d like to thank all officers involved in yesterday’s operation for their professionalism and tireless work despite the level of abuse that they faced."

“The violence we encountered during the operation was coordinated and carried out by a group of people, many wearing masks to conceal their identity, intent on creating as much disorder as possible. Many of those individuals have now been arrested and we have begun securing charges," Smart said.

“The contrast between this demonstration and the other protests we policed yesterday, including the Palestine Coalition march attended by around 20,000 people, was stark. You can express your support for a cause without committing an offence under the Terrorism Act or descending into violence and disorder, and many thousands of people do that in London every week," the police official said.

The British Police proscribed the Palestine Action under anti-terrorism legislation in July.

The proscription made it a crime to support or belong to the organisation.

A person found guilty of violating the ban can face upto 14 years in prison.