Last Friday, the watchdog notified the Met about an investigation into alleged bets placed by a police constable from the Royalty and Specialist Protection Command.
A police officer responsible for the prime minister's security has been taken into custody on suspicion of misconduct in public office, following allegations that they placed bets related to the general election timing.
The officer, who serves on the prime minister's close protection team, was initially suspended by the Metropolitan Police before being arrested and taken into custody, according to BBC.
Mr Rishi Sunak announced 4 July as the date of the general election on 22 May, taking much of Westminster by surprise.
The Gambling Commission is investigating suspected betting violations related to the election date, and has enlisted the Metropolitan Police's assistance.
Last Friday, the watchdog notified the Met about an investigation into alleged bets placed by a police constable from the Royalty and Specialist Protection Command.
The Met promptly referred the matter to their Directorate of Professional Standards, launching an investigation and removing the officer from active duty.
The officer was arrested on Monday, taken into custody, and later released on bail pending further investigation. The Independent Office for Police Conduct has also been informed.
The Royalty and Specialist Protection Command provides close protection services for high-profile individuals, including members of the Royal Family and senior government officials, during their travels and daily activities.
The Gambling Commission is responsible for ensuring gambling activities serve the best interests of consumers and the general public, a spokesperson stated.
The spokesperson said they were conducting an investigation into potential breaches related to the election date, and working to determine if any offences had been committed.
In a separate development, Craig Williams, a top aide to Prime Minister Rishi Sunak, has been accused of placing a £100 wager on a July election date just three days before the PM officially announced the date as July 4.
Williams, who formerly served as the Tory MP for Montgomery and is now running for re-election in the newly formed constituency of Montgomeryshire and Glyndwr, has acknowledged making a "huge error of judgment" but has declined to confirm or deny whether he placed the bet based on confidential information.