Investigation under way into police role in Mitchell case

British prime minister David Cameron has said allegations that a police officer sought “to blacken the name” of former government chief whip Andrew Mitchell are extremely serious.

Mr Mitchell had to quit after it was alleged that he had shouted at officers guarding No 10 Downing Street when they refused to open the main gates to let him pass on his bicycle and told them that they were “f****** plebs” and to “learn your f****** place”.

Mystery witness

His fate was sealed after a Conservative MP received an email from a witness – now revealed to be a police officer – who claimed that he had witnessed the altercation as he stood outside the Downing Street gates with a nephew.

Thirty police officers are now investigating the latest revelations, which have left Mr Cameron infuriated and Mr Mitchell saying that he would “never have believed that this could happen in Britain”.

Mr Cameron said: “A police officer posing as a member of the public and sending an email potentially to blacken the name of a cabinet minister is a very serious issue, and it does need to be seriously investigated.”

Police are “conducting a thorough and well-resourced investigation to get to the truth”, he said, adding that the investigation would be supervised by the Independent Police Complaints Commission: “I think we should allow it to get to the truth.”

The police federation, which rounded on Mr Mitchell after the incident, last night strongly rejected charges that it had been involved “in a stitch-up” because of its anger over pay cuts.

CCTV footage

The arrest of an officer suspected of sending the controversial email was a matter for concern, it said, but this “remains a separate issue to the original claims” made by the Downing Street officers about Mr Mitchell’s alleged behaviour.

“It is disappointing that all information and evidence regarding the original incident was not revealed at the time – if that had occurred perhaps we would not be in the situation we now find ourselves in as a police service,” it went on.

CCTV footage from Downing Street, released to Mr Mitchell under Data Protection Act rules, raises questions about the police log of the event, since the exchanges between him and one officer do not appear to have been argumentative.