A Metropolitan Police officer has been charged with rape.
PC David Carrick, 46, of Stevenage, Hertfordshire, is due to appear via video link at court later.
He was off-duty at the time of the alleged offence on September 4 last year in St Albans, police said.
Met Police commissioner, Dame Cressida Dick, said she was “deeply concerned” at the news, and a referral has been made to the police watchdog.
Mr Carrick is based within the Met’s Parliamentary and Diplomatic Protection Command, Scotland Yard said.
He was charged by Hertfordshire Constabulary on Sunday after his arrest on Saturday.
Mr Carrick has been suspended by the Metropolitan Police, the force said, adding that a referral has been made to the Independent Office for Police Conduct.
Mr Carrick remains in custody and is scheduled to appear via video link at Hatfield Magistrates’ Court on Monday.
Dame Cressida said: “I am deeply concerned to hear the news that an officer from the Met’s Parliamentary and Diplomatic Protection Command has been arrested and now charged with this serious offence.
“I fully recognise the public will be very concerned too.
“Criminal proceedings must now take their course so I am unable to comment any further at this stage.”