A Yorkshire prison did not adequately care for a bullied teenager who hanged himself in his cell.
The damning conclusion came as a coroner ruled Ryan Clark had accidently killed himself at Wetherby young offenders' prison in April 2011.
He had been on remand after being arrested on suspicion of two robberies but was found hanging from a ligature made from a bed sheet suspended from a cell window.
Clark, who was from Leeds, had been in care since he was just 16 months old and had been the victim of verbal abuse and physical threats at the prison.
He was said to be "scared to death" of a lengthy custodial sentence, an inquest jury had heard.
Other failings included poor documentation of Clark's vulnerabilities and susceptibilities; that more support that could have been provided to him; and that Wetherby's "shout out" policy to tackle bullying was ineffective.
Jurors decided Clark's actions were a "cry for help" in the face of threats and that his death was accidental.
Sonia Daggett, Ryan's mother said: "I'm so glad the jury has recognised that Ryan never intended to kill himself. Lessons must be learned to stop pretend self-harm turning to tragedy."
Ruth Bundey, solicitor for Ryan Clark's family welcomed the verdict.
She said: "It is welcome that the jury has recognised the very serious failings in the lead up to Ryan's death. However it is also clear that he was failed by those who were supposed to protect his welfare for a long time before that.
"Over 50% of the children held in Wetherby Young Offenders Institution are 'looked after' children. Ryan's death has raised serious questions about the protections afforded by the state to very vulnerable young people."
We offer our sincere and continuing sympathies to Ryan's family and all those who knew and cared for him.
"Every death of a child in custody is a tragedy and the Youth Justice Board (YJB) takes our responsibility for children in custody very seriously.
"We have noted the jury's findings and will give careful consideration to the issues identified by the inquest and what action they require us to take to make improvements.
"We continue to seek improvement to all aspects of care for children in custody."