A female police officer been arrested on suspicion leaking information to the press over the Downing Street â€œPlebgateâ€ affair which led to the resignation of former chief whip Andrew Mitchell.
The 46-year-old, who works for Scotland Yard’s SO6 diplomatic protection group, was arrested at work in central London on suspicion of misconduct in a public office.
She is the four person arrested over the row.
A team of 30 Scotland Yard officers is investigating whether there was a conspiracy against Mr Mitchell, who resigned after being accused of calling police on duty in Downing Street “â€“â€“â€“â€“ing plebs”.
The arrested officer was present at Downing Street during the incident in September, police confirmed.
Others arrested in the investigation, code-named Operation Alice, include a 46-year-old male police officer who was arrested on Thursday and bailed to return on a date in March.
A 52-year-old Pc, who also works for the DPG, was held on suspicion of misconduct in public office and a 23-year-old was arrested on suspicion of intentionally encouraging or assisting the commission of an indictable offence.
Four other constables in the unit, which is responsible for protecting government officials and diplomats, have been placed on restricted duties over misconduct claims.
All 800 members of the DPG have been told to submit sworn statements to officers investigating the row.
Operation Alice will analyse the statements from every officer in an exercise that could take 2,500 man hours and cost about Â£64,000.
Sir Bernard Hogan-Howe, the Metropolitan Police commissioner, had previously said that a file of evidence on the case could be handed to prosecutors by the end of January.
But Scotland Yard yesterday said that because of “ongoing developments” no interim report had yet been submitted to the Crown Prosecution Service.
The row was sparked when Mr Mitchell had a row with officers who refused to open a vehicle gate for him as he left Downing Street on his bike.
A police log of the incident suggested he called officers “plebs” and swore at them repeatedly.
Mr Mitchell has admitted swearing but denied using the words “plebs”. He later claimed he was the victim of a deliberate attempt to “toxify” the Tories and ruin his career.
An email from a civilian witness backing up the police account of events was also called into question.
By January 16, Operation Alice had cost Â£82,500 since it was set up in December.
The figure, which related to staffing costs, was disclosed in a letter from deputy assistant commissioner Patricia Gallan to Keith Vaz MP, chairman of the Home Affairs Select Committee.
Female police officer arrested in Plebgate row