Twenty-nine people have been arrested in the UK on suspicion of terror offences for holding up signs with the words “I oppose genocide. I support Palestine Action.”

The protest, organised by Defend Our Juries, took place in Parliament Square on Saturday, a few hours after Palestine Action was officially proscribed by the Labour government—at the stroke of midnight on Friday. The proscription order makes membership of, or any expression of support for, the peaceful protest group punishable by up to 14 years in prison.

Police began making arrests after 20 minutes, handcuffing several people, many of them elderly, and carrying them into vans. Among those arrested was 83-year-old Reverend Sue Parfitt.

Head of the Metropolitan Police Sir Mark Rowley in an interview the next morning claimed, “It is not about protest. This is about an organisation committing serious criminality,” and threatened, “If you’re supporting proscribed organisations, then the law is going to be enforced… they’re breaking a serious law.”

These are the first victims of an order—rushed through parliament in less than two weeks—which criminalises the free speech of millions and is aimed at spearheading a total outlawing of opposition to Israel’s genocide of the Palestinians.

The judgement handed down by the High Court on Friday refusing Palestine Action’s request for interim relief from that order—until a judicial review can be held—makes clear the depths of authoritarianism into which the UK is being plunged.

Arriving at this decision, Mr Justice Chamberlain went against opinions submitted by the UN Special Rapporteur on the Promotion and Protection of Human Rights and Fundamental Freedoms while Countering Terrorism, the National Council for Civil Liberties (Liberty) and Amnesty International UK.

Legally, the court was required to decide whether there are serious grounds for considering the government’s order unlawful. If so, and in light of the apparent strength of that case, it was required to balance the harms of refusing or granting interim relief.

On the crucial ground advanced by Palestine Action’s lawyers—that the order is improperly targeted at a “direct action civil disobedience network”—Chamberlain was dismissive. The “language Parliament used” in drafting the Terrorism Act (2000) was clear, and it includes “serious damage to property”.

The UN Special Rapporteur pointed out in his submission that “Protest movements claiming to defend human rights, that are an irritant to property rights or affect certain national security interests, but which do not engage in sustained campaigns of murder, are not typically treated as ‘terrorist’, even where they could technically come within a national terrorism definition.”

Chamberlain acknowledged that “it is sometimes legitimate to interpret a statute more narrowly than its express language suggests, for example in accordance with the principle of legality or consistently with unincorporated international law.”

He nevertheless concluded that it was “not possible” to read the Terrorism Act as “incorporating a restriction on the use of the power against ‘civil society or dissent groups’… If Parliament had intended such a restriction, it would have included it expressly.”

This leaves the door wide open to proscribing a host of political and protest organisations. The government’s order is justified in part with reference to private companies’ “lost revenue”. Where would this leave groups of workers organising a campaign of strikes or blockades?

Chamberlain handed Home Secretary Yvette Cooper a blank cheque when he insisted, “This is not a case where the Secretary of State is said to have acted for some extraneous purpose such as to quell political views with which she disagrees.”

The Court accepted that there was a “serious question to be tried” as to the order’s interference with Articles 10 and 11 of the European Convention on Human Rights—the rights to freedom of expression and association—but only whether this interference is “proportionate” when weighed against “national security”.

That phrase is used 13 times across 26 pages, with Chamberlain at pains to stress the “wide margin of discretion” given to the home secretary “when taking decisions about how to protect the public from risks associated with terrorism.”

The judgment admits that “the materials before the court [providing evidence of those “risks”] are necessarily limited because of the urgency with which this hearing has been listed.” All the Court had access to was Cooper’s ministerial statement introducing the order, which provides so little evidence that Palestine Action’s lawyers were moved to question whether she had advanced “a national security justification for proscription” at all.

But it was enough for Chamberlain that “PA’s targets include both ‘key national infrastructure’ and firms which provide defence supplies to the UK and its allies.” On this basis, “suspending the effect of the order even for a short period would deny the public important protections which the order is intended to confer.” The “public” and arms manufacturers are effectively held to be synonymous.

This supposed threat to national security is held to outweigh massive state attacks on the right to free speech and political organisation.

Lawyers for Palestine Action noted the impact that even a short period of proscription would have, including “a grassroots direct action network built up over five years” being “destroyed overnight. All distribution lists, social media accounts, and literature will be deleted or destroyed. Any funds or property will be immediately deemed terrorist property.”

In some cases, the implications could be deadly. Palestine Action founder Huda Ammori observed—in light of the policy of extrajudicial murder of “terrorists” pursued by the United States—that she “would have to avoid travelling to the Middle East for fear of assassination.”

Palestine Action’s lawyers described the order’s “profoundly chilling effect on freedom of speech at a time of acute public concern about the serious breaches of international law being perpetrated against Palestinians in Gaza.”

The cultural impact was spelled out by Irish author Sally Rooney, whose statement explained, “I will effectively be prevented from speaking at any future public events in the UK, since I could not in good conscience disguise or lie about my principles in public.”

She asks, “Will bookshops go on stocking the work of an author the Home Secretary has branded a ‘terrorist’ simply for supporting a protest group? … [W]ould the BBC continue to screen and promote my work?”

The consequences for an artist living in Britain will be tested by the principled stand of musician Roger Waters, who posted a video after the proscription order went into force stating, “I support Palestine Action. It’s a great organisation. They are non-violent, they are absolutely non-terrorist in any way.”

The video already has well over half a million views. The Zionist Campaign Against Antisemitism (CAA) has said it will seek to bring a private prosecution if Waters is not charged.

Chamberlain agrees in his judgement that the “proscription order will undoubtedly have severe effects on the claimant and many others” and that it “can cast a long shadow over legitimate speech.” But this is precisely the point, he argues, of an order “which aims to disrupt and disable organisations which meet the threshold for proscription and which the Secretary of State and Parliament decide to proscribe.”