Police have arrested more than 20 protesters after a ban on the Palestine Action group came into effect.

The protest group was from midnight on Saturday after a last-minute legal challenge at the Court of Appeal to delay it failed.

The Metropolitan Police said on Saturday afternoon that the protesters had been held on suspicion of committing offences under the Terrorism Act 2000 following a protest in London's Parliament Square.

"The group is now proscribed and expressing support for them is a criminal offence," the force added. "Arrests are being made."

MPs overwhelmingly of Home Secretary Yvette Cooper's decision to ban the protest group under the legislation and Lords have approved the move.

The law change adds to the list of banned organisations along with the likes of al Qaeda, ISIS and Hezbollah, and makes membership of, or support for, the direct action group a criminal offence punishable by up to 14 years in prison.

Even wearing a T-shirt or badge with the group's name on attracts a maximum six-month sentence.

On Saturday, a large number of Metropolitan Police officers circled around dozens of protesters carrying placards that said: "I oppose genocide. I support Palestine Action".

It came after campaign group Defend Our Juries said demonstrators were set to gather in Parliament Square on Saturday holding signs supporting Palestine Action.

Officers who attended the protest were met with cries of "Met Police you are puppets of the Zionist state" and "leave them alone".

Others were heard shouting: "British police off our streets" and "From the river to the sea, Palestine will be free".

A woman seen lying on the floor in handcuffs was carried away by officers and put in a police van.

She said was heard saying: "Free Palestine, stop the genocide, I oppose genocide, I support the rights of the Palestinian people, I support freedom of speech, I support freedom of assembly".

A large group of people crowded around to film the scene.

Officers placed her in a vehicle before returning to the square's Mahatma Ghandi statue.

Chants of "shame" were directed at the police. Most of the officers dispersed at around 2.10pm.

Leslie Tate, 76, a Green councillor from Hertfordshire, said: "Palestine Action are not a violent organisation, and the proscription is wrong.

"This protest is necessary to defend our democracy, and this is the creeping edge of totalitarianism, frankly."

Among those removed by police was Reverend Sue Parfitt, who is 83.

The protest started at about 1.10pm and officers were seen taking people away shortly after 1.30pm.

Ms Cooper announced plans to proscribe Palestine Action after , which police said caused around £7m worth of damage.

Even wearing a T-shirt or badge with the group's name on attracts a maximum six-month sentence.

On Friday, the High Court heard the decision to ban the group was taken before the aircraft were allegedly damaged and as early as March this year.

Huda Ammori, the co-founder of Palestine Action, is seeking to bring a legal challenge against the Home Office with a hearing for permission to bring a judicial review set to take place during the week of 21 July.

On Friday, her lawyers applied for "interim relief" to temporarily block the legislation from coming into force until that hearing, arguing the Irish author Sally Rooney, who wrote Normal People, was among supporters who fear the "ramifications".

But three judges, including the Lady Chief Justice Baroness Carr, refused refused a bid to pause the ban coming into effect pending any Supreme Court bid at about 10.30pm on Friday, less than two hours before the ban was due to come into force.

In their judgment, the judges said: "The role of the court is simply to interpret and apply the law.

"The merits of the underlying decision to proscribe a particular group is not a matter for the court... Similarly, it is not a matter for this court to express any views on whether or not the allegations or claims made by Palestine Action are right or wrong."

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