Extinction Rebellion supporters have superglued themselves in a circle around the Speakers Chair inside the House of Commons.
The protest group read out a speech to the empty Parliament chamber demanding a citizens’ assembly on climate change.
They also held up banners which read “let the people decide” and “citizens assembly now”.
A member also climbed up the scaffolding around Big Ben and held another banner, while two others chained themselves to the railings surrounding the building.
The protest will spark an immediate security review.