LONDON — A bearded man wearing a suit walks on the roof of a London Underground train as a crowd of clearly infuriated commuters yell and point at him.

A few seconds later, another man leaps up and grabs his legs as the protester tries to kick him off. They both fall, and the protester is buried among the angry mob, who seem to attack him on the floor.

Video of Thursday morning’s episode in eastern London , which was circulated widely, illustrated the complicated passions that have been ignited by protests in the British capital by Extinction Rebellion, a group of environmental activists who employ radical disruptive tactics to draw attention to the climate crisis.