A London police officer filmed beating and pushing a by-stander who died shortly afterwards, during protests against the April 2009 G20 meeting, will not face prosecution, the UK Director of Public Prosecutions (DPP) has ruled.

Keir Starmer, the DPP, said a "fundamental disagreement" between pathologists who carried out successive autopsies on the victim, 47-year-old newspaper seller Ian Tomlinson, meant a prosecution for manslaughter would be unlikely to succeed. Starmer is head of the Crown Prosecution Service (CPS) which is responsible for deciding whether to proceed with prosecutions.

The initial post-mortem by Dr. Freddy Patel concluded that Tomlinson died from a heart attack. But two pathologists who carried out subsequent autopsies contradicted Dr Patel's findings. Dr Nat Carey, on behalf of the UK Independent Police Complaints Commission, concluded that Tomlinson's death was the result of internal bleeding as a result of injuries consistent with assault or a fall.

Dr. Patel has since been suspended from doing work for the UK Home Office, and is facing unrelated disciplinary proceedings regarding his conduct of four other autopsies.

The DPP said the police officer, 43-year-old Constable Simon Harwood, could not be prosecuted on a lesser charge of assault because more than six months had elapsed since the incident took place.

Ian Tomlinson's family reacted angrily to the news. His son, Paul King said "The CPS are clearly admitting a police officer assaulted our Dad. Why hasn't there been no charge? Words can't describe how we feel. We feel very let down, very disappointed."

The UK's Daily Telegraph newspaper reported today that Constable Harwood has faced two previous disciplinary investigations over alleged misconduct. The first, concerning an off-duty road rage incident, led to him leaving the Metropolitan Police. He took a job with Surrey Police, where he was again investigated following allegations about his behavior while on duty. He later returned to work for the Metropolitan Police.

Footage of the incident that led to Tomlinson's death shows that Harwood had covered the lower part of his face with a balaclava and concealed identifying numbers on his uniform.

Comments by Internet users on UK news websites overwhelmingly condemned the decision not to charge Harwood.?