These are women of the Red Brigade, among the most eye-catching of the thousands of people who have joined the demonstrations on the climate crisis in the UK capital thoughout October.
The Red Brigade was created by a street-performance group, the Invisible Circus, and made its first political appearance in 2001, in protest against the Iraq war. It joined the Extinction Rebellion movement in April.
The vivid colour "symbolises the common blood we share with all species, that unifies us and makes us one", explained a member.
UK prime minister Boris Johnson described the protestors as "uncooperative crusties", who should stop blocking the streets with their "heaving hemp-smelling bivouacs".