POLICE face being sued for carrying out hundreds of unlawful arrests and trespass if the proscription of Palestine Action is overturned, a leading protest organiser said today.

Demonstrators have been detained under the Terrorism Act for holding signs in support of the non-violent activist group since Home Secretary Yvette Cooper proscribed it under terror laws in July.

More than 500 people are expected to attend the latest sit-down protest organised by Defend Our Juries (DOJ) in Parliament Square this Saturday.

DOJ organiser Tim Crosland said that forces could face legal action should the proscription be overturned in a judicial review, which has been brought by Palestine Action co-founder Huda Ammori.

Speaking at a press conference today, the former government lawyer said that DOJ had received legal advice from Hodge Jones & Allen solicitors and “have specifically asked them if the order is struck down in November, does that open up the possibility for legal claims against the police for unlawful arrest and for trespass to people’s property, and the answer to that is yes.”

Mr Crosland described how police forces are “in disarray” over how to respond to the proscription.

Met Police officers have used section 12 of the Public Order Act to arrest protesters while their counterparts in Cardiff have gone “berserk” extending custody time limits under the Terror Act to search two detained women’s homes and possessions with a Geiger counter, he said.

“We’ll keep going as long as people want to take part in this action, and at the moment it’s hard to keep up with the demand, people are seeing it as a badge of honour for resistance to genocide and for defence of our democratic freedoms,” he added.

“Nobody has been charged, it’s important to say, and there’s a sense that there aren’t going to be charges before the judicial review.

“There will be more actions to come in September and October until the law is struck down, as we believe it will be in November.

“We’re hearing from thousands of people wanting to take part in this action, so it feels like there’s huge energy behind it, there’s a sense that something really important is happening and so what we can say we are expecting there to be all the way through to that legal hearing in November.”

Speaking to the Morning Star, Mr Crosland suggested that trade unions could soon publicly declare their support for DOJ.

TUC and Unite representatives are among those who have expressed support individually, and “that’s an indication of where this could go,” he said.

The University and College Union said in July that the “Prime Minister and Home Secretary are completely wrong to have proscribed Palestine Action, a move which accelerates our slide into authoritarianism.”

No MPs are expected at the protest on Saturday; some have told DOJ that they would be suspended from Parliament for attending, Mr Crosland added.

Ms Ammori told the press conference that the arrests of hundreds of protesters was “a major factor” in a High Court decision to allow her judicial review to go ahead.

She accused the Home Secretary of making “many false allegations publicly” after Home Office officials briefed the Times that Palestine Action could be funded by Iran.

“These are things which I would dispute completely as false statements,” Ms Ammori said.

NHS consultant obstetrician and gynaecologist Dr Alice Clack, who was arrested for holding a Palestine Action sign on July 19, said that she will still attend the protest on Saturday despite a likely suspension from her profession should she be found guilty of a terror offence.

The granddaughter of a Jewish refugee who escaped to Britain added: “My family’s stories taught me the importance of resisting propaganda that seeks to dehumanise others and the necessity of standing against injustice.”

Angie Zelter, veteran protester and founder of the International Women's Peace Service, hoped hundreds of thousands would back the demonstrations.

Cage director Moazzam Begg, a former Guantanamo Bay detainee, said: “The proscription of Palestine Action is the worst of the anti-terror legislation we’ve seen.”