Drug diversion schemes led by police that steer people away from the criminal justice system and into treatment and education services are significantly more effective in reducing reoffending than prosecution, according to a new analysis.

Researchers examined outcomes across 13 English police forces and more than 62,000 criminal incidents over the past four years, finding that people whose cases were dealt with through decriminalisation-style diversion schemes were a third less likely to reoffend than similar individuals prosecuted for drug possession.

A number of police forces in England use formal diversion schemes for people caught in possession of drugs, notably Durham, the West Midlands and Thames Valley. But many forces, even if would-be offenders are not often sent to prison for simple possession offences today, still officially take a law-and-order approach towards illegal drug use.

Prof Alex Stevens, the acting director of the University of Sheffield’s Centre for Criminological Research, who led the research, said: “The evidence is now strong enough that all police forces can be confident in adopting and expanding diversion schemes for people caught in possession of drugs.”

The researchers who conducted the four-year, first-of-its-kind study, funded by the Cabinet Office’s evaluation accelerator fund, are working with the National Police Chiefs’ Council (NPCC) and the College of Policing to help police forces countrywide to adopt police-led drug diversion.

Quantitative data was collected over four years on a cohort of people who were contacted by police forces between October 2021 and September 2022.

Commander Alison Heydari, the NPCC lead for out-of-court resolutions (OOCRs), said the study highlighted the effectiveness of diversion. “Through the ‘national OOCR strategy’, there is a clear commitment to ensuring that eligible individuals are consistently offered appropriate alternatives to prosecution, helping to prevent reoffending while also addressing disparities in outcomes,” she said.

The researchers, however, found that diversion was being used far less than it could be, even in police forces with established diversion schemes, with only a minority of eligible cases diverted as officers chose not to divert eligible offenders. “Police forces now have an opportunity to reduce their costs – and pressure on the courts – by making more use of diversion,” said Stevens, who quit the government’s expert advisory council on drugs in 2019 over the “political vetting” of candidates. “This will require clear leadership, proper training, and a shift in culture at street level.”

Jason Kew, a former DCI at Thames Valley police who led the development of its pre-arrest drug diversion scheme, said forces that embedded diversion schemes could go further still and develop specialist pathways for women.

“Getting this right means fewer women in custody, fewer children lost to the system – and stronger, healthier communities,” said Kew, now a senior practice specialist at the Centre for Justice Innovation. “The question is no longer whether diversion works. It is how boldly we choose to build on it.”

The report also said that people in the most deprived neighbourhoods were most heavily policed and least likely to be diverted, and that black people were less likely to be diverted than white people for similar offences.

Prof Kojo Koram, from Loughborough University’s law school and the author of The Next Fix: The Winners and Losers in the Future of Drugs, said: “For every stage of the drug policing process, from stop and search, to arrest, to sentencing, statistics show that black and minority ethnic people are punished at a much higher rate than white people despite similar rates of use.

“Diversion schemes are a first step towards moving people away from criminalisation, and clearly needed when we look at our overcrowded prisons, but they are still quite a tame policy initiative when compared to full decriminalisation and legal regulation policies being passed across Europe and North America. Britain remains desperately behind the curve on drug policy.”

In 2017, around the time when diversion schemes were first being formally adopted, a Home Office report acknowledged: “There is, in general, a lack of robust evidence as to whether capture and punishment serves as a deterrent for drug use.”

Steve Rolles, the senior policy analyst at Transform Drug Policy Foundation, said: “Diversion still feels like the government wanting to have the benefits of decriminalisation without having to say the word. Despite the obvious benefits of decriminalisation, it does nothing to deal with the harms of the illegal trade. The choice is between putting the government in charge, or leaving organised crime in control.”