The police force in London, which is Britain's largest, faced fresh scrutiny Monday about its vetting procedures after an officer admitted 24 counts of rape and a string of sexual assaults over nearly two decades.

David Carrick's crimes – described by Prime Minister Rishi Sunak's office as "appalling" – is the most high-profile police case since a fellow officer kidnapped, raped and murdered a young woman in 2021.

Then, as now, background checks by the Metropolitan Police in London were found lacking, leaving it battling to regain dented public confidence.

Carrick, 48, appeared in court in London on Monday and pleaded guilty to four counts of rape, as well as false imprisonment and indecent assault against a 40-year-old woman in 2003.

Reporting restrictions were lifted on his admission at a previous hearing in December of 43 charges involving 11 other women, including 20 counts of rape, over a 16-year period to September 2020.

He will be sentenced over two days from Feb. 6.

The Met, which polices a population of more than 8 million people over 1,605 square kilometers (620 square miles) in the British capital, called Carrick a "prolific, serial sex offender."

Met Commissioner Mark Rowley apologized to Carrick's victims, saying he "abused women in the most disgusting manner" and went unpunished due to "systemic failures."

"We have failed. And I'm sorry. He should not have been a police officer," Rowley said in a statement.

The Met revealed that a thorough review of former soldier Carrick's service and complaints record was conducted in October 2021, after he was first charged with rape.

That found he was already on police systems for a series of off-duty incidents before and after he joined the force.

Yet none of those complaints of rape, domestic violence and harassment had led to criminal sanctions or internal disciplinary proceedings.

The Met "failed in two respects," Rowley admitted.

It "should have been more intrusive and joined the dots on this repeated misogyny over a couple of decades" and "should have been more determined to root out such a misogynist," he said.

The police watchdog is now reviewing the Met's handling of Carrick, while a wider probe is under way into other potential misconduct of other officers.

They include more than 1,600 cases of alleged sexual offenses or domestic violence, the Met said.

Failings

A damning report published last November found that a culture of misogyny and predatory behavior was "prevalent" in many police forces in England and Wales, fuelled by lax vetting standards.

His Majesty's Inspector of Constabulary Matt Parr found it was "too easy for the wrong people to both join and stay in the police."

He also highlighted "significant questions" over the recruitment of "thousands" of officers, undermining public trust.

Another report, published last October, found the majority of Met police personnel who were repeatedly accused of misconduct kept their jobs.

"People are getting away both with misconduct but also criminal behavior," senior civil servant Louise Casey said.

Met failings came to light after Wayne Couzens, who like Carrick was an officer in an armed unit protecting MPs and foreign diplomats, killed Sarah Everard in March 2021.

He snatched her from the street in south London by falsely claiming she had broken coronavirus lockdown rules. She was then raped and strangled.

But it later emerged that the Met had failed to take action against him for allegedly exposing himself in 2015.

The Couzens case, and that of several other officers prosecuted for severe misconduct in public office, prompted the Met to promise to root out the corruption.

Met Commissioner Rowley has set up a new unit using tactics usually deployed against organized crime to "go after the racists and misogynists who are undermining us."

Investigators said Carrick met some of his victims through online dating apps or on social occasions and used his position as a police officer to gain their trust.

Chief Crown Prosecutor Jaswant Narwal said he then "relentlessly degraded, belittled, sexually assaulted and raped women."