Joseph Nicolosi, leading advocate of so-called "gay conversion" therapy and prominent anti-gay figure in the US, has died aged 70. Nicolosi, co-founder of the National Association for Research & Therapy of Homosexuality (Narth), died following complications from flu, his clinic confirmed.

Nicolosi was known as a key figurehead in the controversial treatment which he claimed helped reduce gay people's "same-sex attractions and explore their heterosexual potential".

His views led him to make several media appearances during his career, including being interviewed by Oprah Winfrey, Larry King and Stephen Fry.

His wife of 39 years, Linda posted a tribute via Facebook. She said: "Joe was certainly a larger-than-life, one-of-a-kind guy. Never worried about political correctness, he was happy to swim against the cultural tide when he was sure the culture was going in the wrong direction.

"Dr Nicolosi had always hoped for his legacy as the creator of Reparative Therapy to go on. His career was dedicated to helping people align their lives with their deeply held convictions. Anyone, he stressed, is free to live his life as gay; but we are inevitably gendered beings, and our fullest humanity calls us to live out our biological design."

The therapy – which can include the use of electric shocks to deter people from homosexual thoughts – was denounced by major medical associations including the American Psychiatric Association and the American Psychological Association and is banned in several US states.

Janet Weisz, Chair of the UK Council for Psychotherapy said in 2015: "For a therapist to agree to try and 'cure' or 'reduce' same sex attraction would be unethical and potentially harmful. I am clear this practice has no place in the modern psychotherapy profession."