Andrew Mitchell 'pleb' row police make second arrest Still from CCTV footage, provided by Channel 4, of Andrew Mitchell at the Downing Street gate. Photograph: Channel 4 Detectives investigating the so-called "plebgate" row involving the former Tory chief whip Andrew Mitchell have arrested a 23-year-old man. The man, who is not a police officer or a member of police staff, was arrested at his home at 8pm on Wednesday night. A Scotland Yard spokesman said: "Officers investigating the circumstances surrounding a police officer's claim to have witnessed an incident in Downing Street in September 2012 have arrested a man on suspicion of intentionally encouraging or assisting the commission of an indictable offence on or around 14 December 2012." He said the man, who was questioned at a London police station, was released on Thursday morning and bailed to return next month. It is the second arrest made during the inquiry. Last Saturday, an officer from Scotland Yard's diplomatic protection group, SO6, was held on suspicion of misconduct in a public office after the force received fresh information regarding the alleged unauthorised disclosure of information. The officer, who was not on duty at the time of the incident in Downing Street in September, was released on bail the following day and suspended from duty. Metropolitan police officers accused Mitchell of calling them "fucking plebs" after they declined to allow him to ride his bike through the Downing Street security gates. The row over the exchange led to the Tory MP resigning as chief whip in October, after a month-long fight to fend off the claims and save his career. The MP admitted swearing at the officers, but denied using the word "pleb." The row was reignited on Tuesday night when Channel 4 News published details of an email written by a man who claimed to have witnessed the altercation, but who was later revealed to be a police officer. The email, which was virtually identical to the official police log of the incident, was sent to John Randall, the officer's local MP, who is also the deputy chief whip, at 9.52pm on 20 September. The revelation has provoked a bitter row between Downing Street and Scotland Yard, with the prime minister accusing the officer of trying to "blacken" Mitchell's name by drawing up an allegedly false account of a confrontation with armed officers. Amid signs that Scotland Yard was stung by criticism from Westminster and questions about the integrity of the force, it has announced that 30 officers are working on the investigation into claims that evidence was faked.