Pimps and sex offenders have joined the police, a review commissioned following the murder of Sarah Everard by Met diplomatic protection officer Wayne Couzens has revealed.
He abducted the 33-year-old in Clapham, south London on March 3, 2021, under the pretence of an arrest and took her to the outskirts of Dover where he raped and killed her.
Following the shocking crime, watchdogs HM Inspectorate of Constabulary and Fire and Rescue Services looked into the vetting checks of police officers across England and Wales.
It reviewed 11,277 officers and staff across eight forces, 725 vetting files, more than 200 complaint and misconduct investigations, and interviewed people.
It discovered that some staff had criminal records and families linked to organised crime.
The report added warnings an officer could pose a threat to the public were ignored, links to criminal behaviour were dismissed and officers were being transferred across forces when they had allegations of misconduct against them.
Inspectors said vetting decisions were "questionable at best" in more than 100 cases and in 68 of those disagreed clearance should have been given.
Matt Parr, Inspector of Constabulary, said: "It is too easy for the wrong people to both join and stay in the police.
"If the police are to rebuild public trust and protect their own female officers and staff, vetting must be much more rigorous and sexual misconduct taken more seriously.
"It seems reasonable for me to say that over the last three or four years, the number of people recruited over whom we would raise significant questions is certainly in the hundreds, if not low thousands... it is not in the tens, it is at least in the hundreds."
He said poor vetting of prospective staff could not be excused on the pressure to meet the government's target to hire 20,000 new officers by next year.
He added: "The marked decline in public trust for policing is undoubtedly linked to the prevalence of some of these dreadful incidents we have seen in recent years, and you should have a higher standard of who gets in and who stays in if you are going to look to reduce those kinds of incidents."
Although the review did not look specifically into Couzens', it did question if better checks could have stopped him from getting a job.
It also said an "alarming number" of female officers claimed they had been subject to "appalling behaviour by male colleagues" and improved guidance was needed on how to act in a workplace.
Home Secretary Suella Braverman said it was "disappointing that HMICFRS have found that, even in a small number of cases, forces are taking unnecessary risks with vetting".
"I have been clear that culture and standards in the police need to change and the public's trust in policing restored. Chief constables must learn these lessons and act on the findings of this report as a matter of urgency."
National Police Chiefs' Council chairman Martin Hewitt added: "Chief constables, supported by national bodies, will act on these recommendations and put the problems right because we cannot risk predatory or discriminatory individuals slipping through the net because of flawed processes and decision-making.
"The confidence of the public and our staff is dependent on us fixing these problems with urgency, fully and for the long term. Police chiefs are determined to do that."