British campaigners reported Saturday that the sheer volume of people who showed up in London‘s Parliament Square to support the nonviolent advocacy group Palestine Action presented a major challenge for the Metropolitan Police, who had threatened to arrest anyone supporting the organization.

The campaign group Defend Our Juries reported that as of 4:00 pm local time, at least 200 people had been arrested for joining the protest, where more than 1,000 sat silently in the square with many displaying signs that read: „I oppose genocide. I support Palestine Action.“

Others held signs reading, „Is this why you joined the police?“ as officers arrested demonstrators including National Health Service workers; a blind man using a wheelchair; author Jonathon Porritt; and former Guantánamo Bay detainee Moazzam Begg, who now advocates for wrongly-imprisoned people swept up in the War on Terror.