Metropolitan Police officer David Carrick has been charged with 12 more sexual offences, including three counts of rape.
The 47-year-old had previously been charged with 29 offences against 10 victims.
The original charges covered crimes such as rape, coercive and controlling behaviour and sexual assault.
Now, as part of an ongoing investigation by Hertfordshire Constabulary, he has been charged with a further 12 offences.
Seven of them are related to one of the existing 10 victims, while five relate to an 11th victim.
The additional offences are alleged to have taken place between 2004 and 2020.
They are:
• Four counts of sexual assault which allegedly took place between 2018 and 2020
• Three counts of rape that allegedly took place between 2018 and 2020
• One count of rape which allegedly took place in 2004
• Two counts of assault by penetration which allegedly took place between 2003 and 2009
• One count of attempted rape which allegedly took place in 2009
• One count of rape which allegedly took place in 2015.
He is now due to appear at Westminister Magistrates' Court on Monday 21 March.
PC Carrick was first arrested back in October and charged with one count of rape.
As a result, he was immediately suspended.
Prior to his arrest, he was attached to the Parliamentary and Diplomatic Protection Command.
Metropolitan Police said it recognises these are "serious and concerning allegations" and referrals have been made to the Independent Office for Police Conduct.
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