In the western world at least, it is normal for new treatments to undergo rigorous testing before being accepted into mainstream medicine. Often, the complaint from those who might benefit from therapies is that approval takes too long. This excess of caution may be frustrating for those who need help but far worse would be a system in which patients became guinea pigs in unregulated mass experiments with potentially life-altering and irremediable consequences. Such is the case with puberty blockers which for years have been fed to children in this country who are confused about their identity and sexuality. The use of these substances to impede physical development in youngsters who question their gender, despite an absence of sound scientific understanding of the long-term effects, is a medical scandal of the first order, a reckless exercise in 21st-century quackery.

It is right, therefore, that the National Health Service in England has called time on the routine prescribing of puberty blockers after the horror story at the gender identity clinic within London’s Tavistock NHS trust. Yet children and parents intent on taking this dangerous path will still be able to access them through NHS Scotland and private doctors. The job is only half complete. This “therapy” needs to be reined in entirely across the UK.

Puberty blockers, which inhibit the development of characteristics like breasts and facial hair, have been prescribed for hundreds of under-16s on the NHS since 2011. Children were referred to the clinic in a decade when gender identity was taking on a more militant and ideological aspect — the NHS found itself under constant pressure from groups like the charity Mermaids, which promoted this radical intervention. At first, most of those referred for treatment were boys, average age 11. What should have immediately struck a chord with clinicians treating them was that many were from troubled backgrounds. More than a quarter had spent time in care and more than a third hailed from families with mental health problems. Autism was another common thread.

Over time, girls replaced boys by a ratio of six to one, a strange, shapeshifting malady.

A sensible layman might have concluded that worries about gender identity were more likely to be symptoms of anxiety and depression rather than the cause of it. The natural concerns of youngsters coming to terms with their sexuality could also be misinterpreted by themselves and their parents as gender dysphoria — fear of being attracted to one’s own sex being mistranslated into unhappiness with one’s body.

The case for puberty blockers was that they allowed troubled children to pause while coming to terms with their gender identity. These hormone inhibitors were characterised as an on-off switch that could be flicked with impunity. This was a startling example of medical arrogance. Little was known about the effect of blockers — used also in chemical castration — on developing young bodies. It is now accepted that they affect bone density and, potentially, cognitive development. At the very least, this little-understood chemical cosh separates teenagers from their peers. Patients are frozen in time as their friends develop. Those lost years cannot be regained. And, far from being a pause, blockers tend to presage chemical and surgical procedures that are irreversible.

There will be a small number of people who will forever feel that they were born in the wrong body, and the option to change that is a right — for a mature adult. Children suffering gender dysphoria require kindness, understanding and, if necessary, mental health support. They should not be set on a path to a place from which they cannot return.

There are still too many loopholes. Private doctors should be banned from prescribing blockers. The Scottish government, too, should consider why it continues to sanction this dangerous practice.