A gay journalist who went undercover to expose the methods of gay conversion therapists is organising a campaign to stamp out the controversial therapy.

Patrick Strudwick revealed last week how two therapists, one of whom was an advisor to homophobic former MP Iris Robinson, had tried to turn him straight through “unethical” methods.

The premise of gay conversion therapy is that gay people can be turned straight and that homosexuality is often caused by a lack of a father figure or sexual abuse as a child. In some cases, NHS funding pays for the treatment.

Critics say it does not work and can lead to severe mental health problems. Research published last year found one in six therapists and psychiatrists had tried to turn a gay person straight.

Mr Strudwick has now set up a campaign group called Stop Conversion Therapy Taskforce (SCOTT) to expose such therapists and persuade professional bodies to condemn them.

He told PinkNews.co.uk: “We want to get various professional bodies in mental health to change their codes of conduct on trying to change sexuality. Currently it’s all very vague, they don’t specifically condemn the practices in their guidelines.

“Also, as a part of that, we want to root out therapists and psychiatrists who are practising these techniques and ultimately bring an end to them through exposing them, as well as disrupting their meetings. We want to highlight the risks and the dangers.”

He added that the ultimate aim was to prevent religious groups from offering ‘counselling’ which aims to change sexual orientation.

Mr Strudwick wrote about his experiences with ex-gay therapy in the Independent last week.

One therapist, named only as Linda, tried to convince him he must have been sexually abused as a child by a member of his family.

Mr Strudwick said: “It was incredibly disturbing to hear that. I was speechless and disgusted.

“In reality, people only go into this when they’re vulnerable – can you imagine what would happen? The amount of lives which would be ruined.

“No matter how gay-affirmed you are, subconsciously, it starts to embed. Essentially, it’s bad practice and completely unethical.”

He set up a Facebook group this week which now has nearly 1,000 members. A meeting will be held tomorrow evening to discuss how an upcoming ex-gay convention in Northern Ireland can be protested.

Dominic Davies, the founder and director of Soho-based Pink Therapy, works with LGBT clients to help them feel positively about their sexual orientation and gender identity.

He is supporting the campaign and told PinkNews.co.uk: “My major concern is that there is no scientific basis, no evidence for these therapies. Really, they’re just supporting their religious and political agendas through fairly sophisticated techniques.”

He said that some could cause “quite severe” mental health problems, including self-harm, suicide attempts and low self-esteem.

He said: “It’s a pretty dangerous approach. I am very concerned that it is being practiced by people who are accredited and ought to know better.”

Mr Davies added that he felt professional bodies such as the UK Council for Psychotherapy and the British Psychological Society were on side with the campaign.