More than 500 Palestine Action supporters are set to stage a protest in London with the intention of provoking mass arrests and overwhelming police.

Campaigners have planned for Left-wing activists and members of the Muslim community to deliberately flout terrorism laws by declaring their support for the banned group in Parliament Square on Saturday.

To do so would be an offence under the Terrorism Act 2000 and would be punishable by up to 14 years in prison.

In a warning to organisers, the Metropolitan Police charged three supporters of the group on Thursday, who became the first to face such charges.

More than 200 protesters have been arrested during marches by Defend Our Juries, who organise the gatherings, since the Palestine Action ban came into force last month.

The group was outlawed by the Home Secretary following an alleged attack on aircraft at RAF Brize Norton and its supporters have described the ban as a “gross abuse of power” designed to hinder expressions of support for the Palestinian cause.

Dept Asst Commissioner Ade Adelekan, of Scotland Yard, warned: “The Met is very experienced at dealing with large-scale protests, including where the protest activity crosses into criminality, requiring arrests.

“While we will not go into the specific details of our plan, the public can be assured that we will have the resources and processes in place to respond to any eventuality.

“Anyone showing support for Palestine Action can expect to be arrested. I would once again urge people to consider the seriousness of that outcome.

“An arrest under the Terrorism Act can have very real long-term implications – from travel, to employment, to finances. Also, as we have seen this week, it is very likely an arrest in these circumstances will lead to a charge.”

A spokesman for Defend Our Juries said: “Whoever thought these things would be happening in this country? These attacks on the right to protest just show how Yvette Cooper’s conflation of direct action with terrorism would put us on a dangerously slippery authoritarian slope, if it is allowed to stand.”