The Metropolitan Police suspended a sergeant last night, after a video taken during the G20 protests showed an officer with a concealed shoulder number apparently striking a woman with a baton.
Scotland Yard was facing fresh allegations of brutality over the footage, which appeared to show an officer hitting a woman with the back of his hand, telling her to "get back now", before drawing his baton and striking her on the legs.
The woman, who is heard swearing at the police officers, falls to the ground amid horrified cries from bystanders. Unlike his colleagues in the pictures, the officer appears to have his shoulder number hidden, with the epaulettes on his jacket concealed by strips of grey material.
The incident is believed to have taken place at 3.30pm on 1 April, near the Bank of England where about 5,000 people had been penned in by police cordons.
The footage prompted a wave of criticism. David Howarth, the Liberal Democrat justice spokesman, called for a "full-scale inquiry", adding: "The fact that this video shows another example of an officer with his number obscured assaulting a member of the public indicates that there is a systematic problem here, not just a series of individual acts of misconduct."
Shami Chakrabarti, director of the human rights group Liberty, said: "It is very difficult to understand what justifies a gargantuan police officer assaulting a smaller woman for having the audacity to complain."
The Labour MP David Winnick called the incident "outright police brutality" and said the latest footage strengthened his demand for the Home Secretary Jacqui Smith to make a statement about police tactics at the G20 when Parliament returns next week.
Yesterday, activists posted an appeal on the internet for witnesses to come forward with a view to making a complaint to the Independent Police Complaints Commission (IPCC). It is already looking into the death of Ian Tomlinson, a 42-year-old newspaper-seller who died of a heart attack minutes after allegedly being pushed to the ground by a police officer near the Bank of England during the G20 protest.
As the new video came to light, the police watchdog was already facing criticism after claiming that "no CCTV footage" had been used in the area around Royal Exchange Passage, where the video showed Mr Tomlinson being assaulted. Interviewed on Channel 4 News last Thursday, the IPCC's chairman Nick Hardwick said there was no CCTV evidence of alleged police assaults. "We don't have CCTV footage of the incident," he said. "There is no CCTV footage - there were no cameras in the location where he was assaulted."
Yesterday morning, after pictures were published clearly showing cameras in the area, the IPCC was forced to change its stance, saying Mr Hardwick had been mistaken. "At this point, Mr Hardwick believed that he was correct in this assertion - we know now this may not be accurate," the IPCC said in a statement. "There are cameras in the surrounding area."
A Scotland Yard spokesman said that the evidence had been passed to the IPCC with the identified officer suspended pending investigation.