PC David Carrick has been charged with three further rape offences against a 12th victim.
The suspended Metropolitan Police officer, who is from Stevenage, had previously been handed 41 charges against alleged 11 victims.
Among the existing charges are rape, coercive and controlling behaviour, and sexual assault.
Hertfordshire Police handed the 47-year-old officer three new charges today (Monday, May 9).
A statement by PC Carrick's employer in London read: "We recognise that these are extremely serious and concerning allegations.
"Referrals have been made to the Independent Office for Police Conduct as the investigation has progressed.
"The Met’s Directorate of Professional Standards continues to monitor developments closely and will provide whatever support it can to Hertfordshire officers."
PC Carrick was arrested in last October on a single charge of rape.
Between October 2021 and March 2022, the Crown Prosecution Service authorised officers in Hertfordshire to charge him with 41 offences against 11 alleged victims.
He previously pleaded not guilty to some of these charges at St Albans Crown Court in December.
The charges which PC Carrick received today bring the total number of charges to 44.
He is due to appear at Westminster Magistrates' Court via video link on Friday, May 13.
His trial was due to start on Tuesday, April 26, but St Albans Crown Court confirmed it had been postponed.
Before his suspension, PC Carrick was attached to the Met's Parliamentary and Diplomatic Command.
He was suspended after his arrest.
The Met said any misconduct proceedings associated with PC Carrick cannot take place until after the outcome of a criminal case.
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