Extinction Rebellion protest action is continuing in London despite police ordering activists to end their gatherings across the capital or risk arrest.
Lawyers questioned whether the ban, made under public order legislation already used to restrict the action to Trafalgar Square, was legal.
Anti-Brexit barrister Jo Maugham QC said the move was “a huge overreach” of police powers, while human rights lawyer Adam Wagner called it “draconian and extremely heavy-handed”.
Green Party MEP Ellie Chowns, who was arrested in Trafalgar Square, Green MP Caroline Lucas and shadow policing and crime minister Louise Haigh also spoke out against the ban.
Ms Haigh said: “This is a grotesque overreaction and extremely worrying attack on basic civil liberties.”
Police moved in to clear Trafalgar Square on Monday evening, telling protesters to leave the site by 9pm or risk arrest.
On Tuesday, Metropolitan Police Deputy Assistant Commissioner Laurence Taylor said the protest ban was brought in after “continued breaches” of the condition limiting the demonstration to Trafalgar Square.
He said: “This was an operational policing decision to help us get London moving again.
“After nine days of disruption we felt it is entirely proportionate and reasonable to impose this condition because of the cumulative impact of these protests.
“A significant policing operation continues and we will take robust action against anyone engaged in unlawful protests at locations targeted by Extinction Rebellion.”
The activists defied the order and, on Tuesday morning, the group’s co-founder, Gail Bradbrook, was filmed climbing the entrance to the Department for Transport in Westminster.
Extinction Rebellion said other protesters had glued themselves to the building.
It said activists were calling on the Government to explain its plan to meet a net-zero emissions target within the carbon budget of the UK.
Mr Maugham said on Twitter: “We believe the section 14 Order is invalid – that it amounts to a huge overreach of the statutory power – and likely reflects the enormous political pressure the Met is under.
“It exposes the Met to all sorts of risks – of legal challenges to validity, of civil claims for wrongful arrest with aggravated damages and so on – merely because this Government cannot tolerate peaceful protest.”
Human rights lawyer Mr Wagner questioned whether the Public Order Act allows for a city-wide ban on protests.
In a series of tweets, he said: “As things stand, five XR protesters standing on the pavement outside my house would be breaking the law. As would school children with XR banners in a park. The ban seems draconian and extremely heavy handed even given previous disruption.
“We have a right to free speech under article 10 and to free assembly under article 11 of the (annex to the) Human Rights Act. These can only be interfered with if the interference is lawful and proportionate. I think the police may have gone too far here.”
In response to the police action, an Extinction Rebellion (XR) statement said its “rebels” would take “a moment to pause and remember why we are here”.
It added: “Extinction Rebellion will let the Trafalgar Square site go tonight.
“The International Rebellion continues.”
On Twitter, XR’s London branch labelled the clearing of protesters from the square as “an outrage”.
It also tweeted: “Today, an unprecedented, political, decision has been taken to shut down peaceful protest calling out the government for inaction in the face of crisis.”
As of 5pm on Monday, police said there had been 1,445 arrests in connection with the eight days of XR protests in London.
Mr Taylor said officers had made more than 90 arrests on Monday as protesters targeted the City of London, the capital’s financial district.
On Monday night in Trafalgar Square, four people in a so-called peace tent, who had locked themselves together, were cut out of their locks with machinery.
Pam Williams, 71, glued herself to the spot where her tent stood as police arrived to take it.
Speaking to the PA news agency, she said: “I’m refusing to leave and I’ve glued myself to the ground. My husband has taken away the tent, the police haven’t got it. I shall stay here until I’m arrested.”
MEP Ms Chowns said she was arrested after “standing in solidarity” with protesters in Trafalgar Square.