A prison inmate killed himself hours after his mother phoned the jail concerned for her son’s safety, the Prison and Probation Ombudsman said.
Warren Sampson’s mother had rung HMP Chelmsford on 4 September 2015 because of messages he had left.
A report said “no-one spoke to [him] about this or tried to gauge his risk”, a response that was “inadequate”. The 29-year-old was later found hanged.
A Prison Service spokeswoman said the jail had since made improvements.
Mr Sampson was remanded at the Essex prison on 4 August after being charged with assaulting his partner and was placed under suicide and self-harm procedures from 12 August until his death.
The Ombudsman said these “did not operate fully effectively” and “staff missed signs that Mr Sampson’s vulnerability and risk of suicide had increased” on 4 September.
After a mental health review, a counsellor was concerned about his anxiety and that he had made a noose, but wing staff and others did not “explore this further”.
A prisoner in the next cell to Mr Sampson said he looked like “a broken man” and told an officer while gesturing a “hanging” motion, but the officer said she could not remember what had been said or if any gesture was made.
He had also called his partner and mother that afternoon and could not get through but left messages suggesting he intended to kill himself, the report said, including one to his partner which said “if she had answered the phone he would have told her she had just saved his life”.
His mother called the prison between 19:15 and 19:30 BST and officers did go to his cell but did not ask about his safety concerns.
Mr Sampson was found hanged in his cell between 21:40 and 21:45 and was pronounced dead an hour later.
The ombudsman investigates every prison death and although Mr Sampson died three years ago, this report has only now been published.
This October, the charity Inquest said the jail, which has one of the highest suicide rates in the country, made “the same systemic failings with dismal regularity”.
A Prison Service spokeswoman said: “This is a tragic case and our thoughts remain with Mr Sampson’s family and friends.
“We accepted all the recommendations from the Prisons and Probation Ombudsman and the prison has since made a number of improvements to the work it does to prevent suicide and self-harm.
“The prison has provided specialist training for staff to help them identify, monitor and support vulnerable offenders, and have also recruited an extra 60 prison officers in the last year giving staff more time to provide dedicated support to every prisoner.”
A prison inmate killed himself hours after his mother phoned the jail concerned for her son’s safety, the Prison and Probation Ombudsman said. Warren Sampson’s mother had rung HMP Chelmsford on 4 September 2015 because of messages he had left. A report said “no-one spoke to [him] about this or tried to gauge his risk”, a response that was “inadequate”.