At least 60 people will be prosecuted for "showing support" for the recently proscribed Palestine Action group, in addition to three already charged, London's Metropolitan Police said on Friday.
"We have put arrangements in place that will enable us to investigate and prosecute significant numbers each week if necessary," the Met said in a statement.
More than 700 people have been arrested since it was banned as a terrorist group in early July, including 522 people arrested at a protest last weekend for displaying placards backing the group -- thought to be the highest ever recorded number of detentions at a single protest in the UK capital.
"The decisions that we have announced today are the first significant numbers to come out of the recent protests, and many more can be expected in the next few weeks," said Director of Public Prosecutions Stephen Parkinson.
"People should be clear about the real-life consequences for anyone choosing to support Palestine Action," said Parkinson.
The first three people were charged earlier this month with offences under the Terrorism Act for backing Palestine Action, after they were arrested at a July demonstration.
According to police, those charged for such offences could face up to six months imprisonment, as well as other consequences.
"I am proud of how our police and CPS (prosecution) teams have worked so speedily together to overcome misguided attempts to overwhelm the justice system," Met Police Commissioner Mark Rowley said.
In a statement following the latest mass arrests, Interior Minister Yvette Cooper defended the Labour government's decision, insisting: "UK national security and public safety must always be our top priority."
"The assessments are very clear -- this is not a non-violent organisation," she added.
The government outlawed Palestine Action on July 7, days after it took responsibility for a break-in at an air force base in southern England that caused an estimated pound7.0 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 has insisted that Palestine Action was also suspected of other "serious attacks" that involved "violence, significant injuries and extensive criminal damage".
Critics including the United Nations, Amnesty International and Greenpeace have slammed the proscription as legal overreach and warned that the ensuing arrests threaten free speech.
The UK's Liberal Democrat party said that it was "deeply concerned about the use of terrorism powers against peaceful protesters".
