Last year, Keira Bell and an unnamed mother, won a case in the UK High Court, to stop children under 16 being given puberty blockers. That decision has now been overturned in the court of appeal.

In a judgment handed down on Friday, the lord chief justice, Lord Burnett, Sir Geoffrey Vos and Lady Justice King said it had been “inappropriate” for the high court to issue the guidance.

The appeal court judges stressed that it was established legal principle that “it was for clinicians rather than the court to decide on competence [to consent]”.

A spokesperson said: “The judgment upholds established legal principles which respect the ability of our clinicians to engage actively and thoughtfully with our patients in decisions about their care and futures. It affirms that it is for doctors, not judges, to decide on the capacity of under-16s to consent to medical treatment.”

The ruling came as a disappointment to many, especially in light of the increasing number of adults presenting with trans regret after being put on medication as teenagers.

Bell said she planned to seek leave to appeal to the supreme court, adding: “A global conversation has begun and has been shaped by this case. There is more to be done. It is a fantasy and deeply concerning that any doctor could believe a 10-year-old could consent to the loss of their fertility.”

Mrs A, the other claimant alongside Bell, said: “A child experiencing gender distress needs time and support – not to be set on a medical pathway they may later regret.”

Binary spokeswoman, Kirralie Smith, said the ruling was not entirely disappointing.

“The emphasis is still on informed consent. Rather than the court making those decisions the onus is now on the doctor,” she said.

“Medical professionals still have to be absolutely certain the child can give informed consent, which is highly unlikely in most cases.

“It should give them pause to embark on the pathway of medication knowing that an increasing number of people now regret their transition and they could be held responsible for wrongly assuming the child could give informed consent.”