Police have been accused of manhandling a Tiananmen Square survivor away from a human rights protest before raiding his home.
Shao Jiang, 47, was seized outside Mansion House in central London shortly before Chinese president Xi Jinping arrived.
Footage shows Mr Jiang standing in the road waving banners before a group of officers dash over and drag him away.
Two other women, Sonam Choden, 30, and Jamphel Lhamo, 33, were also arrested at the scene.
Campaigners have accused the Met Police of deliberately targeting Tibetan demonstrators to try to please China.
All three campaigners allegedly had their houses raided by police, who seized computers and phones.
The Met Police confirmed a man and two women were arrested at around 4.30pm on Wednesday.