Investigations by the General Medical Council (GMC) into a psychiatrist who attempted to “cure” gay people, and who worked with shamed former MP Iris Robinson, are taking place in private.

Dr Paul Miller, the therapist referred to by Mrs Robinson when she made her now-infamous remarks about gay people in June 2008, is under investigation by the GMC’s Medical Practitioners Tribunal Service (MPTS) for allegedly trying to take financial advantage of a patient between 2004 and 2010.

Hearings on Dr Miller’s fitness to practice began on 8 April and are scheduled to run until 3 May, but will, unusually, be closed to the public and press.

The MPTS said in a statement: “All fitness-to-practise hearings are held in public, except in circumstances where the panel consider that the particular circumstances of the case outweigh the public interest in holding the hearing in public.”

Dr Miller worked with Mrs Robinson as a part-time advisor when she was chair of the Health Committee at Stormont.

Speaking after a gay man was beaten up in Northern Ireland, she said she knew Dr Miller as a “lovely psychiatrist” who worked with her and was able to turn gay people straight.

Dr Miller is still under investigation by the GMC for his work running the Abeo umbrella organisation for therapists who try to cure homosexuality. He has previously said that “same-sex attraction” in men stems from “core un-met needs” such as the lack of a father figure.

He was exposed when gay journalist Patrick Strudwick went undercover to receive treatment from him.

Mr Strudwick had two webcam therapy sessions with Dr Miller, in which the psychiatrist encouraged him to become aroused and spoke about his own struggles to fight attraction to men.

The methods were condemned by Professor Michael King, a psychiatrist from University College and Dominic Davies, the founder and director of Soho-based Pink Therapy.

Following the experience, which he wrote about in the Independent, Mr Strudwick reported Dr Miller to the General Medical Council.

Mr Strudwick told the BBC: “It was very disturbing because I was acutely aware during the sessions of the effect this would be having on a vulnerable young person had I been genuinely seeking treatment.

“I felt disgusted and abused by his inappropriate sexual remarks during the sessions. To hear this from a psychiatrist during a session, it was like being sexually assaulted.”

In 2012, Dr Miller was on the Council of Reference for a London gay cure therapy conference entitled ‘The Lepers Among Us’.