Shocking footage of a Brighton G20 protester being hit in the face by a police officer then whacked on the legs has emerged.

The woman, has been named as Nicky, is said by her family to be recovering from the ordeal at her Brighton home.

The attack happened on April 2 during a memorial protest at the death of newspaper seller Ian Tomlinson, who died of a heart attack after being shoved to the ground by police during the G20 protests the day before.

Nicky told The Guardian: "I'm shocked at the way the police treated me." She added: "I just want to thank the guy [25-year-old IT assistant Tristan Woodwards] who took that video," she said.

Her sister Natalie Thompson said Nicky been “deeply traumatised and terrified,” by the attack, which was captured on film.

Ms Thompson told the Evening Standard: "My sister was terrified after the attack and very traumatised. She did not want to come forward earlier because she feared nothing would be done but once the footage was released on the internet, she decided to do something about it," she said.

The footage, along with pictures of her injuries, has been handed to the Independent Police Complaints Commission, which is investigating the case.

During the film, the officer hits the protester in the face using the back of his hand, telling her: “Go away”. She shouts back “I’m a woman” and he then strikes her on the legs with his baton, despite crowds of people with cameras surrounding them.

The sergeant, from the Territorial Support Group, has been suspended, just days after a fellow officer from the group was suspended in connection the death of Ian Tomlinson.

Shami Chakrabarti, director of Liberty, also called on the Commissioner to respond. She said: "As these two officers came from the same unit, it raises very serious questions about their chain of command.

"Why were both officers so apparently ready to use violence? Why were the identity numbers of both obscured?

"Did they go out to prevent trouble or to start it? Policing the capital is too important to leave these questions hanging."