Dr Mark Pakianathan is Consultant Physician in HIV Medicine & Sexual Health at Guy’s & St Thomas’ NHS Trust where he leads on Sexual & Gender Diversity Sexual Health within a large HIV treatment centre and open access sexual health service. He has over 25 years of experience of working in Sexual Health mostly in London where his career has had a strong focus on working with marginalised populations including inner city youth, sex workers and prisoners. He has a research interest in Chemsex and in his career pioneered specialist co-located services for sexual health and substance use disorders for gay, bisexual and other men who have sex with men in South London. He has also developed and run experiential training on Chemsex clinical communication which was replicated as a resource for training professionals across Europe.  He is a strong advocate for holistic compassionate care