Children and young people should not be put in the position to decide whether they can take powerful gender transition drugs, a former transgender patient has said.

Keira Bell is backing legal action against the NHS to stop young people being given hormone blockers and cross-sex hormones like she was when she was a teenager.

Bell, who has returned to living as a woman, said that giving such drugs and offering surgery to children struggling with gender dysphoria was "unnecessary" and "certainly should not be offered to someone under the age of 18 when they are emotionally and mentally vulnerable", The Telegraph reports.

She and others are suing the Tavistock and Portman NHS Trust, which runs the UK's only gender identity development service (GIDS) for children, because of concerns over how it is treating gender dysphoria in young people.

The other people involved in the legal action are the mother of a 15-year-old autistic girl who is on the waiting list for hormone treatment, and Susan Evans, who formerly worked at the Tavistock clinic as a psychiatric nurse.

Speaking after a hearing last week, Bell described the current system as "affirmative" and suggested it did not give children enough room to think about why they have gender dysphoria.

"I do not believe that children and young people can consent to the use of powerful and experimental hormone drugs like I did," she said.

"I believe that the current affirmative system put in place by the Tavistock is inadequate as it does not allow for exploration of these gender dysphoric feelings, nor does it seek to find the underlying causes of this condition.

"The treatment urgently needs to change so that it does not put young people, like me, on a torturous and unnecessary path that is permanent and life-changing."