Plebgate: Second officer arrested over alleged conspiracy that led to resignation of former chief whip Andrew Mitchell

Six policemen are now under investigation over the affair

Six policemen are now under investigation over the “Plebgate” affair, Scotland Yard revealed today, as a second officer was arrested over an alleged conspiracy that led to the resignation of the former chief whip Andrew Mitchell.

A 46-year-old member of the Diplomatic Protection Group (DPG) was arrested at work and taken to a central London police station for questioning on suspicion of misconduct in public office over alleged leaks to the media about the affair.

The officer was not present at the time of the dispute between Mr Mitchell and officers on duty outside Downing Street when officers claimed that he swore at them and used the term pleb. Mr Mitchell admits swearing but denies directing it at the officers and using the politically-toxic term.

Details of the confrontation first appeared in the media on September 19, which led to a campaign against the politician by factions of the Police Federation and Mr Mitchell’s eventual resignation. However CCTV pictures and the revelation that an email backing up the officers’ story was sent by a colleague led to Tory MPs claiming that Mr Mitchell had been brought low by a police plot.

The policeman is the second officer to be arrested over the affair. A 52-year-old colleague was arrested in December over the same offence and has been bailed until late February.

A man, 23, who was not a policeman, was also arrested on December on suspicion of aiding misconduct in public office and is also on bail.

It emerged today that four other officers from the DPG, which protects embassies, foreign dignitaries and sensitive sites like Downing Street, had been issued with disciplinary notices informing them that they faced misconduct inquiries. Three of them have been moved to restricted duties, Scotland Yard said.

Metropolitan Police Commissioner Sir Bernard Hogan-Howe, has said that he would embark on a “relentless pursuit of the truth” in an investigation – Operation Alice – that has cost tens of thousands of pounds. It is being run by the force’s own disciplinary unit and supervised by the Independent Police Complaints Commission.

However critics have raised concerns that the high-profile inquiry is being carried out by officers from the same force as the people they are investigating, instead of bringing in outside officers.

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