A 14-year-old boy left with serious brain damage as a result of suffering a "non-accidental injury" when small is critically ill and should not be resuscitated if his condition worsens, a High Court judge has decided.
Mr Justice Mostyn heard that the teenager suffered from cerebral palsy and was told that his condition had reached a "pitch of crisis".
He concluded that not resuscitating would be lawful and in the teenager's best interests.
The judge analysed medical evidence about the boy at a private hearing in the Family Division of the High Court in London.
He heard that the teenager had been adopted at the age of four after being injured when "very young" - but that adoptive placement had broken down and the boy had lived with foster carers for a number of years.
Mr Justice Mostyn described the case as "terrible".
The judge said the boy lived in the north of England but could not be identified.
A lawyer representing an NHS trust with responsibility for the boy's care had asked the judge to make a ruling on resuscitation.
Barrister Claire Watson outlined detail and told Mr Justice Mostyn that the case was "extremely tragic".
She said specialists felt that any medical intervention would cause the boy pain and distress - and would be futile and unethical.
Miss Watson made an urgent application for a ruling late on Thursday.
She told the judge that the boy was having increasing respiratory difficulties.
Miss Watson said the teenager's adoptive parents still had parental responsibility but had not had any contact with him for some time.
She said, in those circumstances, trust bosses wanted a judge to take responsibility for decisions about resuscitation and further treatment.
"It's a terrible case," said Mr Justice Mostyn.
"When he was very young, as a result of a non-accidental injury, he suffered serious brain damage and developed cerebral palsy."
The judge added: "He was adopted at the age of four (but) the relationship with the adoptive parents has broken down."
He said medical evidence showed that treatment and resuscitation options would be risky, likely to cause the boy pain and distress and be futile.
And he said he was satisfied that there should be no further resuscitation was the right option.