Over 500 people are set to participate in a protest against the UK government’s ban on the direct action group Palestine Action, putting to the test a pledge by the Metropolitan Police to arrest anyone showing support for the proscribed organisation.

Campaign group Defend Our Juries (DOJ) is organising the protest on Saturday in Parliament Square to demand the reversal of the group’s proscription, saying that the protest would only go ahead if at least 500 people committed to joining.

As of Monday evening, the group said that as many as 1,000 people had signed up, confirming on Tuesday that it would go ahead.

The protest will involve participants holding cardboard signs reading: “I oppose genocide. I support Palestine Action.”