Gay rights campaigners were celebrating "a watershed moment" yesterday after doctors said so-called "conversion therapy" designed to change sexuality was discredited and harmful.
More than two-thirds of doctors at the British Medical Association's annual meeting in Brighton approved a motion backing a call for the Royal College of Psychiatrists and other mental health standards bodies to reject such treatments and ban their use in their codes of practice.
Health departments should also investigate alleged cases of conversion therapy being funded by the NHS, the meeting agreed.
The vote follows a year-long undercover investigation published in The Independent in February. Patrick Strudwick, a journalist and campaigner, posed as a "patient" to reveal how evangelical therapists – some operating within the NHS – tried to "reorient" homosexual men and women using techniques developed in the US. One of the people Mr Strudwick interviewed described his treatment as "psychological torture".
Mr Strudwick called yesterday's vote a "watershed moment in the struggle for gay equality".
He added: "My undercover investigation for The Independent, which prompted this motion, highlighted the fact that not only are psychiatrists and psychotherapists still peddling these abhorrent techniques, but that in some cases the NHS are paying for it.
"Hopefully, anyone involved in the so-called treatment of homosexuality will realise that the medical profession considers them dangerous charlatans, and will reconsider their beliefs. I also sincerely hope that any vulnerable gay person who is unhappy about their sexuality takes notice of this motion and realises that it is the world that needs to change, not them."
Tom Dolphin, vice-chair of the BMA's junior doctors committee who proposed the motion, said: "Sexuality is such a fundamental part of who a person is, that attempts to change it just result in significant confusion, depression and even suicide. You can't just wish away same-sex attraction no matter how inconvenient it might be."
But Cardiff consultant neurophysiologist Gareth Payne said there was no "gold standard" evidence that conversion therapy did not work and was harmful. He said it was important to respect the wishes of patients who asked for the therapy.