Extinction Rebellion has won a High Court challenge against the Metropolitan Police over a London-wide ban on protests.
The police imposed it last month, prohibiting any assembly of more than two people linked to the protests dubbed the ‘autumn uprising’.
However, judges have ruled that the legislation used to impose the ban does not cover “separate assemblies”.
Lawyers for the group described the police action as “hastily imposed”.
The Met had argued the ban was the only way of tackling disruption caused by protests.
Announcing their judgement, Lord Justice Dingemans and Mr Justice Chamberlain said the Met had no power to impose the ban because the act does not cover “separate assemblies”.
During 10 days of protests beginning on 7 October, Extinction Rebellion activists called for urgent action by the government to tackle climate change.
Protesters shut down areas around Parliament and the Bank of England, and targeted London City Airport.
Police had tried to restrict the protesters to Trafalgar Square, under Section 14 of the Public Order Act.
However, the ban was lifted four days later, with police saying that it was no longer necessary because the stretch of protests, dubbed the ‘autumn uprising’, had ended.
Claimants bringing the legal challenge included the Green Party’s Caroline Lucas and Baroness Jenny Jones, Labour MPs Clive Lewis and David Drew, and Mr Monbiot.
During the hearing, Phillippa Kaufmann QC, for Extinction Rebellion, told the court the move was “wholly uncertain, an abuse of power and irrational”.