Plebgate: 30 police officers now working on investigation

David Cameron also expressed concern yesterday that a police officer tried to “blacken the name” of the former Cabinet minister.

Scotland Yard has vowed to “get to the truth” of allegations that a police officer falsely claimed to have witnessed the “Plebgate” row that ultimately led to the resignation of Mr Mitchell in October.

The Met’s investigation is being supervised by the Independent Police Complaints Commission (IPCC).

The officer at the centre of the row is said to have written to his local MP, posing as a member of the public, giving details of the altercation that took place when the senior Tory attempted to cycle out of the main gates in Downing Street.

Number 10 said the claims – which emerged after a member of the diplomatic protection squad was arrested – were “exceptionally serious”.

The Metropolitan Police Service (MPS) said yesterday it was conducting a “thorough and well-resourced investigation” that could look at conspiracy.

In a statement it said: “The allegation that a serving police officer fabricated evidence is extremely serious. It goes to the very heart of the public’s trust in the police service.

“The Metropolitan Police Service is conducting a thorough and well-resourced investigation to get to the truth of the matter as quickly as possible.

“On Saturday, an investigation into the alleged unauthorised disclosure of information was reopened. On Saturday evening, an officer was arrested on suspicion of misconduct in public office.

“The investigation is looking at the alleged unauthorised disclosure of information and the circumstances surrounding a police officer’s claim to  have witnessed an incident in Downing Street.”

CCTV footage of the incident, which was broadcast for the first time on Tuesday, appears to contradict parts of a leaked police log detailing the row.

The footage, broadcast by Channel 4 News, appears to show there were few members of the public passing by at the time, apparently contradicting police records.

Mr Mitchell has demanded a full probe into the police account of events and insisted the e-mail – sent to MP John Randall – was key to the loss of his job. “I always knew that the e-mails were false, although extremely convincing,” he said. “It has shaken my lifelong  support and confidence in the police. I believe now there should be a full inquiry so we can get to the bottom of this.”

At Prime Minister’s Questions yesterday, David Cameron said: “A police officer posing as a member of the public and sending an e-mail potentially to blacken the name of a Cabinet minister is a very serious issue.”