In his ruling on Wednesday, Lord Justice Digemans said: "Separate gatherings, separated both in time and by many miles, even if coordinated under the umbrella of one body, are not a public assembly within the meaning of the Section 14 of the 1986 Act".
However, the judges noted there are powers within that act which may be used lawfully to "control future protests which are deliberately created to 'take police resources to breaking point"' - one of Extinction Rebellion's aims.
Assistant Commissioner Nick Ephgrave said the decision to ban the protests was not taken lightly.
Tobias Garnett, a human rights lawyer working with Extinction Rebellion, said the movement was "delighted" with the judgment on what he called "an unprecedented and unlawful infringement on the right to protest".
Lawyers representing XR said the Met now faces claims for false imprisonment from "potentially hundreds" of protesters who were arrested after the illegal ban was imposed. "The police are getting more and more strong powers that they are misusing - and that's absolutely unacceptable".
"Non-violent civil disobedience is essential to democratic politics - in fact there would be no democratic politics without it".
Priest pays tribute to 'bubbly and courageous' Amelia Bambridge
Amelia Bambridge never returned to the Nest Beach Club Hostel following a party about 40 minutes away at Police Beach in Koh Rong. Police did not speculate on what happened to Amelia but earlier this week suggested said she may have drowned .
Speaking in a Facebook Live broadcast outside the court, she said: "The police can over-step the mark".
The protests cost £24m ($NZ48.5m) to police and led to 1828 arrests, with 165 people charged with offences, the Met says.
The Metropolitan Police used Section 14 of the Law of Public Order initially to restrict the protest action to Trafalgar Square, but after "continuous infractions, quot; of the order, the agents moved to clean the area".
Extinction Rebellion protesters chained together as they block the road outside Westminster Abbey on October 7, 2019 in London, England.
"After more than a week of serious disruption in London both to communities and across our partner agencies, and taking account of the enormous ongoing effort by officers from the Metropolitan Police Service and across the United Kingdom to police the protest, we firmly believed that the continuation of the situation was untenable", he said.
He added: "I want to be clear; we would not and can not ban protest". "The condition at the centre of this ruling was specific to this particular protest, in the particular circumstances at the time".
Police, however, said the protests were hugely disruptive to London and action planned on the London Underground posed a threat to the safety of customers and staff, according to the court ruling.