Police in London arrested at least 365 people Saturday for supporting Palestine Action, at the latest and largest protest backing the group since the government banned it last month under anti-terror laws.

The Metropolitan Police said it made the hundreds of arrests, thought to be one of the highest ever at a single protest in the UK capital, for "supporting a proscribed organization".

It also arrested seven for other offences including assaults on officers, though none were seriously injured, it added.

The government outlawed Palestine Action in early July days after it took responsibility for a break-in at an air force base in southern England that caused an estimated £7 million ($9.3 million) of damage to two aircraft.

The group said its activists were responding to Britain's indirect military support for Israel amid the war in Gaza.

Britain's interior ministry reiterated ahead of Saturday's protests that Palestine Action is also suspected of other "serious attacks" that involved "violence, significant injuries and extensive criminal damage".

But critics, including the United Nations and NGOs like Amnesty International and Greenpeace, have lambasted the move as legal overreach and a threat to free speech.

'Unprecedented'

A group called Defend Our Juries, which organized Saturday's protests and previous demonstrations against the ban, said "unprecedented numbers" had risked "arrest and possible imprisonment" to "defend this country's ancient liberties".

"We will keep going. Our numbers are already growing for the next wave of action in September," it added.

Attendees began massing near parliament at lunchtime bearing signs saying "oppose genocide, support Palestine Action" and other slogans, and waving Palestinian flags.

Psychotherapist Craig Bell, 39, was among those holding a placard.

He branded the ban "absolutely ridiculous". 

"When you compare Palestine Action with an actual terrorist group who are killing civilians and taking lives, it's just a joke that they're being prescribed a terrorist group," he told AFP.

As police moved in on the demonstrators, they applauded those being arrested and shouted "shame on you" at officers.

"Let them arrest us all," said Richard Bull, 42, a wheelchair-user in attendance.

"This government has gone too far. I have nothing to feel ashamed of."

Defend Our Juries had claimed only a "fraction" of the hundreds who turned out had been detained, but the Met insisted that "simply isn't true" and that all those showing support for Palestine Action would be arrested.

The London force noted some of those there were onlookers or not visibly supporting the group.

NGOs opposed

The Met also detailed how the hundreds arrested were taken to temporary "prisoner processing" points, where their details were confirmed and they were either instantly bailed or taken into custody elsewhere.

Police forces across the UK have made scores of similar arrests since the government outlawed Palestine Action on July 5, making being a member or supporting the group a criminal offence punishable by up to 14 years in prison.

Police announced this week that the first three people had been charged in the English and Welsh criminal justice system with supporting Palestine Action following their arrests at a July 5 demo.

Seven people have so far been charged in Scotland, which has a separate legal system.

Amnesty International UK Chief Executive Sacha Deshmukh wrote to Met Police chief Mark Rowley this week urging restraint be exercised when policing people holding placards expressing support for Palestine Action.

The NGO has argued arrests of such people are in breach of international human rights law.

A UK court challenge against the decision to proscribe Palestine Action will be heard later this year.

by Alexandra Del Peral