The group, which has also targeted defence firms in Britain with links to Israel, accuses Britain’s government of complicity in what it says are Israeli war crimes in Gaza.

Hundreds of demonstrators gathered near parliament in central London on Saturday to protest against the ban, with many holding up signs that said: “I oppose genocide. I support Palestine Action.”

Police had warned ahead of Saturday’s demonstration that anyone showing support for the group would be arrested. Source: PA / James Manning

London’s Metropolitan Police said people had been detained for a number of offences, including assaulting police officers and supporting a proscribed organisation.

Palestine Action’s ban, or proscription, puts the group alongside al-Qaeda and ISIS and makes it a crime to support or belong to the organisation, punishable by up to 14 years in prison.