Legal experts have said it is "unlikely" that the parents of missing boy Ashya King had committed an offence by taking him out of hospital - but warned the legal system would not permit religious beliefs to override the medical needs of a child.
Prof Penney Lewis, of King's College London, said it was possible the child could be taken into foster care if they are found and refuse to cooperate, but more likely than not it would be dealt with in the courtroom, with a judge giving consent to a procedure.
Ashya's parents are thought to be Jehovah's Witnesses.
She said there had not been any legal cases surrounding the medical treatment of children of Jehovah's Witnesses since the 1990s.
It's because the law is so clear that religious beliefs will not be permitted to override the clinical needs of a child.
Ashya King's parents told the Daily Mail they fled the UK after being told NHS treatments would leave him with life-long disabilities.
The head of the police force which applied for a European Arrest warrant against the parents of Ashya King has now urged their release.
A British mother whose son's life was saved by proton therapy has told ITV that she defied NHS doctors' advice to pursue the treatment.