Five US policemen in Birmingham, Alabama have been fired for beating an unconscious suspect who had crashed his car during a police chase.

Video of the police beating an unconscious Anthony Warren has only just been made public, despite numerous police having seen it following a 2008 police pursuit which ended when Warren crashed his car.

The video, captured by a camera mounted on the dashboard of one of the police cars, shows Warren driving at speed along a motorway, pursued by at least three police cars. He swerves around one vehicle before hitting and injuring a police officer on foot.

Prosecutors who prepared and successfully prosecuted Warren for assaulting the policeman he struck discovered the video in March. It shows Warren thrown from the car window and lying on the ground not moving, before police rush over and begin beating him.

At least one policeman jumps onto Warren with his fist raised and another uses a baton to hit him. Warren does not move throughout the attack.

The footage emerged as state lawyers were preparing a case of attempted murder against Warren for the policeman he hit on the road.

District Attorney Brandon Falls said the video police provided as evidence stopped before the footage of the beating and he only saw the full version by chance a week before the trial.

Lawyers for Warren said he was hospitalized after the incident and was not aware that he had been beaten until the video came to light.

Police Chief AC Roper said the police, who were not identified, were all long serving who had acted in a “shameful” manner.

Warren pleaded guilty to aggravated assault and was given a 20-year prison sentence.