Systemic failures in prisons, the criminal justice system and community agencies are contributing to the deaths of children and young people in custody, a report has said.
The lack of action over the past decade is a "devastating indictment of bad practice", former chief inspector of prisons Lord Ramsbotham said.
Nine children and more than 190 other young people aged 24 and under have died in prisons or secure training centres since calls for a review went unfulfilled following the death of 16-year-old Joseph Scholes 10 years ago, campaigners said.
The criminal justice system and community services "have demonstrably let young people down, for all the wrong reasons, for far too long", Lord Ramsbotham said.
"Too often 'tough' talk about crime and punishment does not result in the authoritative action needed to rectify the flaws in our criminal justice system," he wrote in the foreword to the report called Fatally Flawed.
"Until and unless named individuals are made responsible and accountable for ensuring that things happen, nothing will happen.
"I think that it should be a matter of serious concern that the findings in Fatally Flawed echo what has been said, repeatedly, for years, and are a devastating indictment of bad practice."
Children and young people are being failed by the systems set up to safeguard them from harm, the report by the Prison Reform Trust and the Inquest campaign group found.
A Ministry of Justice spokeswoman said: "Every death in custody is a tragedy for families and friends and has a profound effect on staff and other prisoners.
"The rate of self-inflicted deaths has fallen by approximately 40% since 2004, but we are committed to further reducing the numbers of deaths in custody."