Failures by two councils led to a homeless 16-year-old boy being forced to spend nine months living in a tent and having to sell his belongings to survive, an inquiry has found.
Kent County Council and Dover District Council have been criticised by local government ombudsman Anne Seex for their "inexcusable" handling of the teenager's case.
She said the failures of the two local authorities could have "tipped him into a spiral of drug use and crime" and caused him physical and mental ill-health.
The investigation found he spent nine months sleeping in a tent, sometimes in snowy conditions, in various parts of rural Kent, or on friends' sofas. He sold or gave away most of his possessions to pay friends who let him stay. His tent was vandalised, his feet were often wet, and he lost weight and developed a chest infection.
In her report, Ms Seex said Kent County Council failed to assess the "remarkably determined and resilient" boy, referred to only as "J", as a child in need and accommodate him. Dover District Council failed to accept him as homeless and provide suitable temporary accommodation or contact Kent children's services about him.
The report said the boy became homeless at 16. As a younger teenager, he had been taken into care by Kent County Council and placed with foster parents. He returned to his mother but she told him to leave when he objected to her relationship with a drug user. He applied to Dover District Council for housing but was turned away.
The ombudsman found maladministration because Kent County Council failed to respond to being told about the boy and failed to fulfil its duties to him under the Children Act 1989. Dover District Council failed in its duties under the Housing Act 1996 and failed to follow its joint protocol with Kent. The ombudsman recommended that the councils apologise in writing to the boy and each pay him £5,500.
Jenny Whittle, Kent County Council's cabinet member for specialist children's services, said: "There is no mistaking that the system as a whole failed. We accept our role in that and offer our sincerest apologies to this young man."
Dover District Council apologised for its handling of the case and said recommendations by the ombudsman are already in place to prevent a repeat. A council spokesman said: "We continue to make improvements to our working practices. The council is deeply sorry for any hardship suffered as a result of its actions before these improvements were made.
"The remedy proposed by the local government ombudsman will be actioned as soon as authority is obtained at the next meeting of the full council."