It comes ahead of an update in Parliament on plans to proscribe the group under terror laws.

Britain said on Monday it would use anti-terrorism laws to ban the campaign organisation Palestine Action, making it a criminal offence to belong to the group after its activists damaged two UK military planes in protest at London's support for Israel.

Palestine Action protesters have clashed with police in Trafalgar Square after they were banned from protesting outside Parliament. On Sunday evening the Metropolitan Police imposed an exclusion zone around Parliament, with protesters facing arrest if they enter the area.