A Met Police officer has pleaded guilty to charges of false imprisonment and actual bodily harm.
PC Sam Grigg, 36, used duct tape to restrain Natasha Rabinowitz in a house in Twickenham, south-west London, on December 2 last year.
Ms Rabinowitz and Grigg were known to each other, it is claimed.
Grigg, who was attached to the South West Basic Command Unit, was suspended from duty after being charged.
He was off duty at the time of the offence.
Ms Rabinowitz, aged in her 20s, suffered minor injuries but did not require hospital treatment.
Appearing via video-link at Kingston Crown Court from HMP Wandsworth on Thursday, Grigg pleaded guilty to false imprisonment and assault occasioning actual bodily harm.
John Howey, defending, said: “Mr Grigg accepts that he tied up the complainant. He takes no issue with anything she says.”
Judge Georgina Kent ordered a pre-sentence report and adjourned the sentencing hearing to February 10 at the same court.
She said: “This is a serious offence.
“The ordering of the report is not an indication of the outcome.”
The incident was reported on December 6 last year and Grigg was charged two days later, appearing in custody at Westminster Magistrates’ Court on December 8.
In a statement published on Thursday, commander Savell said: “PC Grigg’s behaviour was totally unacceptable and I know it will cause concern among members of the public. He’s let down the Met and his colleagues who are committed to keeping the people of London safe.
“We took immediate action to suspend PC Grigg from duty when his offending came to light and we will now look to commence misconduct proceedings at the earliest opportunity.
“We are determined to have a Met that the public can trust, with officers that people feel comfortable to approach. When someone fails to meet these standards, we will take action to remove them from our organisation.”