Extinction Rebellion activists are planning to sue the police for false imprisonment after winning a High Court challenge over a ban on protests that brought London to a standstill.

Up to 400 protesters who were arrested stand to win total compensation of about £1 million in the wake of today’s legal ruling.

The direct action group said activists would be encouraged to use any taxpayer funded compensation to pay for future protests and legal cases.

The case was brought by seven XR supporters, including two Labour MPs Clive Lewis, a shadow minister, and David Drew, MP for Stroud, Gloucs, where the movement was launched.

The Metropolitan Police said today the policing of the Extinction rebellion Autumn Uprising had already cost the force £24 million and urged the Government to introduce new laws to combat the threat posed by climate protests.

Two senior High Court judges ruled today that a police decision to impose a ban on Extinction rebellion in London at the height of the protests in October was unlawful. The ban had prevented any assembly of more than two people linked to the group’s Autumn Uprising.

Police said today the law under Section 14 of the Public Order Act was 30 years old and needed urgent updating to cope with modern protests.