In an extraordinary move, Judge Anthony Hayden made the teenager a ward of court, following a request by the boy's local authority, saying he wanted to "keep this lad alive". The court heard that two of the boy's teenaged brothers had been killed while fighting with Al-Qaeda's Syrian affiliate, Al-Nusra Front, and a third had been injured.
Describing the family's "extraordinary history", Martin Downs, the lawyer for the local authority, said one of the boy's friends had also been killed in Syria, while his uncle is a former Guantanamo Bay detainee. The case was brought before the High Court after local authority staff learned that the boy's relatives were planning to take him on a trip to Dubai next month.
The judge described the boy, who has joint Libyan and British nationality, as "a vulnerable young person" and said the local authority was concerned that he "may wish to follow the path which his brothers have walked".
"He has grown up in modern Britain in an extraordinary family -- a family where the male members are patently committed to waging jihad in war-torn Syria," Hayden said.
The boy is currently living with his mother, who the judge said was "exhausted with grief", and there were concerns that she was unable to properly discipline him. In making the teenager a ward of court, effectively taking away the legal power of his parents, the judge confirmed that he could not now be taken out of England and Wales without judicial permission.
Addressing the issue of the teenager's human rights, the judge concluded: "The balance falls clearly in protecting this young man, ultimately from himself." He ruled that the boy could be named, although he allowed the local authority to be named as Brighton city council, on England's southern coast.
An estimated 700 Britons are believed to have gone to Syria since the conflict there began, including young men hoping to fight with militant groups or women intending to marry jihadists.