Around 150 demonstrators are expected to protest at a ‘gay cure’ conference in London tomorrow.

The conference, which has been denounced by gay groups, will feature Joseph Nicolosi, who claims reparative therapy can ‘cure’ homosexuality.

It is expected to be held at the Emmanuel Centre in Marsham Street, central London.

Held by the Anglican Mainstream Organisation, the event will have “a special focus on how religious professionals and friends/relatives can respond biblically and pastorally to those struggling with unwanted SSA (same-sex attraction)”.

According to the organisation, the conference is “ideal for clergy, rabbis, psychologists, therapists, educators and others concerned about the plethora of sexual issues confronting us in today‚Äôs society, including mentoring the sexually broken, the sexualisation of culture, pornography, the Bible and sex, and marriage, the family and sex”.

A Facebook event detailing the peaceful protest already has around 150 attendees, with another 300 who said they may attend.

Organiser Nicolas Chinardet told PinkNews.co.uk he has confirmed with police that the protest will go ahead, starting at 1pm.

The event has been roundly criticised by gay advocacy groups.

A spokesperson for the Lesbian and Gay Foundation said: “It is worrying to hear of this conference aimed at promoting such a deplorable and dangerous approach to therapy, and giving a platform to homophobic ideas.

“We encourage people to access Gay Affirmative Therapy, rather than internalise the homophobic beliefs of others.”

The Gay and Lesbian Humanist Association (GALHA) has also spoken out.

GALHA secretary David Christmas told PinkNews.co.uk: “The fact that the whole premise is riddled with absurdities does not make it any the less dangerous. For the past 30 years, mainstream medicine and science have accepted that homosexuality is in no sense an illness, and as such, by definition, cannot be cured.”

Other groups involved in promoting the protest include Stonewall, the Green Party, the Lesbian and Gay Christian Movement, the Queer Youth Network and the Gay Activists Alliance.