The police may let violent suspects go if the public do not support their efforts to make arrests, a senior representative said after footage of officers being punched and kicked on a London street was shared thousands of times online.

In the video, filmed on Saturday night, a policewoman is sent falling towards a bus by a flying kick from a man. She had been trying to use incapacitant spray to help a male colleague.

The clip, posted by Nehemiah Adams, captain of Guildford City football club, had the caption “South London at night . . . Lol.” A person narrating says: “Oh dear me, [the attacker] just kung-fu kicked her . . . I’m getting this all live, boys and girls, thought I’d just