Ethnic disparities in police diversion and criminalisation for drug possession in England: A study of 32,758 incidents

Introduction: Police-led drug diversion schemes have expanded across England, yet little is known about whether their use reproduces established ethnic disparities in policing outcomes.

Methods: Using individual-level data from 32,758 incidents recorded by 15 police forces (covering 38% of England's population), we conducted a cohort study to estimate ethnic differences in the likelihood of: (i) being offered diversion for suspected drug possession; and (ii) receiving a criminal sanction. Mixed-effects logistic regression models were used to adjust for age, sex, suspected drug type and police-force area, with missing data addressed via Bayesian chained imputation.

Results: We found substantial disparities. Compared with White suspects, Black suspects had significantly lower odds of receiving an offer of diversion (odds ratio 0.75, 95% confidence interval 0.65–0.87), while Asian suspects had significantly higher odds (odds ratio 1.25, 95% confidence interval 1.09–1.43). For criminalisation, Asian suspects were less likely than White suspects to receive a criminal sanction (odds ratio 0.81, 95% confidence interval 0.74–0.89), while Black suspects showed no statistically significant difference.

Discussion and Conclusions: These findings extend long-standing evidence of unequal policing, showing that ethnic disparities persist at the earliest decision points of drug law enforcement—even within schemes intended to reduce criminalisation. The results underscore the need for police forces to monitor and remediate disproportionality in diversion decisions. Future work should investigate mechanisms underpinning officers' diversion decisions and assess whether differential access to diversion contributes to cumulative inequalities in police-community relations and downstream criminal justice outcomes.