The Metropolitan Police said the officer was taken into custody on Monday on suspicion of misconduct in a public office and has since been bailed pending further inquiries.
The arrest comes a week after a close aide to the Prime Minister and candidate for Montgomeryshire & Glyndwr Craig Williams said he was “fully cooperating” with a Gambling Commission investigation into a bet he made about the upcoming General Election.
Mr Williams made a bet with Ladbrokes in Montgomeryshire, reportedly on May 19, three days before Prime Minister Rishi Sunak announced the date of the election outside Downing Street.
He said in a statement last Wednesday that he was ‘cooperating’ with ‘routine enquiries’ but added: “I don’t want it to be a distraction from the campaign. I should have thought through how it looks.”
Police said the arrest of the Royalty and Specialist Protection Command this week had followed information handed to them by the Gambling Commission.
They said the matter was immediately referred to the Met’s Directorate of Professional Standards and the officer was also removed from operational duties.
The matter has also been referred to the Independent Office for Police Conduct (IOPC), the force added.
The Gambling Commission is leading the investigation into the alleged betting offences, which is running parallel to the Met’s probe.
In a statement, the Gambling Commission said: “Currently the commission is investigating the possibility of offences concerning the date of the election.
“This is an ongoing investigation, and the commission cannot provide any further details at this time.”