Self-inflicted prison deaths in England and Wales have increased by 23% in a year, while drug abuse continues to plague facilities despite repeated recommendations to tackle the problems, the prisons watchdog has found.

The number of prison deaths also rose by 6% to 334 in the financial year 2018-19, despite an unexplained reduction in the number of prisoners dying from natural causes, the prisons and probation ombudsman said.

The ombudsman said it was not possible to give a precise figure for the number of drug-related deaths, but highlighted that “one of the most worrying aspects” of its report was “the apparent ease with which prisoners were able to access drugs”.

Some prisons were struggling to stem the supply of and demand for contraband despite having “sound drugs policies” and “doing their best” to limit illegal substances on site, the report found.

Sue McAllister, overseeing her first annual ombudsman’s report, said: “We continue to make the same recommendations repeatedly, sometimes in the same establishments, and often after recommendations have previously been accepted and action plans agreed to implement them.”

However, she said she was unaware exactly how many were repeat recommendations.

The report showed there were 91 self-inflicted deaths during 2018-19, up from 74 the previous year. This figure meant 27% of deaths in prisons in the past year were self-inflicted, up from 23% in the previous 12 months.

In one case, a 31-year-old, who had a long history of substance misuse, including the use of psychoactive drugs, previously known as legal highs, accidentally set himself on fire while smoking a drug in his cell at Hewell prison in Worcestershire.

The report found the unnamed prisoner pressed his emergency cell bell and called for help but it was 16 minutes before an officer found him. The man was said to be conscious but unable to comply with staff instructions and had severe burns to most of his body.

The report found the prisoner had accidentally set himself on fire and may not have reacted initially because he was under the influence of a psychoactive substance. He died two days later.

The ombudsman said the delay in responding to the prisoner was unacceptable, and the response time was more than three times longer than the target of five minutes. A disciplinary investigation was subsequently opened.

McAllister said: “It was a very tragic and distressing incident. The number of drug-related incidents on any one day can be significant. In this case, it was dismissed as just another drugs related-incident.

“I’m not saying there is a culture that it [the cell bell] doesn’t matter, but I think there is a sense sometimes that it is overwhelming.”

Another prisoner, 32, was found hanged after having told a cellmate at HMP Manchester he was “panicking” about his drug debts to a fellow prisoner.

The report found the number of deaths from natural causes dropped from 188 to 180 during the year, although the report was unable to explain the cause of this.

There were four homicides in prisons in England and Wales in 2018-19, down from seven the previous year.

Prisons and Probation Minister, Lucy Frazer QC MP, said: “Any self-inflicted death is a tragedy, which is why we have trained more than 25,000 staff in suicide and self-harm prevention and assigned each inmate a dedicated keyworker for support.

“We are also spending £100m on improved security measures to stop drugs which fuel violence and self-harm, improving support during the often difficult first few days in custody, investing £2.5 billion in modern prison places which support effective rehabilitation and have recruited almost 4,400 more staff in the last three years.”

• In the UK and Ireland, Samaritans can be contacted on 116 123 or email jo@samaritans.org or jo@samaritans.ie. In the US, the National Suicide Prevention Lifeline is 1-800-273-8255. In Australia, the crisis support service Lifeline is 13 11 14. Other international helplines can be found atwww.befrienders.org.