Twenty-three people died in or following police custody last year, the highest number for a decade.
The Independent Office for Police Conduct (IOPC) said the figure included three people who died in a police cell, five in hospital after becoming unwell in custody, and nine who were taken ill at the scene of their arrest and died in hospital.
There were four fatal police shootings – including the three London Bridge terror attackers – compared to six last year. In total, 14 people died in or following custody in 2016/17.
Twelve of the 23 people who died in 2017/18 had mental health concerns, while 18 were users of drugs or alcohol.
Seventeen had been restrained or had force used against them by police or others before they died, but the use of force did not necessarily contribute to their deaths. Of these people, nine were white and eight were black.
There were 29 road traffic deaths, down three from 2016/17, 17 of which were related to police pursuits, down from 28 last year. Eight deaths were as a result of emergency response incidents, the highest figure since 2004/05.
A total of 57 people apparently took their own lives following police custody, the same number as the previous year.
The IOPC investigated 170 other deaths following police contact, up from 132 the previous year, which the watchdog said reflected an increase in the number of investigations rather than deaths.
Of these, 146 followed contact with police after concerns were raised for the person’s welfare, and among those 45 died following a missing person report and 43 after fears about their risk of self-harm, suicide or mental health issues.
Twenty-one were linked to domestic incidents.
Liberal Democrat Home Affairs Spokesperson Ed Davey said: “Every death in police custody is a human tragedy, and today’s rising figures are a reminder that as a society we must do better.
“Most of the 23 people who died last year, in or following police custody, had mental health problems or issues with alcohol or drugs.
“While the police will be the first to admit they want to do better, Parliament needs to ask the question – when we ask the police to act as proxy mental health nurses, are we asking too much of officers?”