Dr Weir is a Consultant Physician, currently in private practice at 10 Harley Street, London. His NHS post was as Consultant Physician at the Royal Free Hospital, London, where he was appointed in September 1987. His main specialty was infectious and tropical disease, much experience of which had previously been gained through working at Ahmadu Bello University Medical School in Nigeria. In addition he was an examiner for the Royal College of Physicians for the Diploma of Tropical Medicine and Hygiene from 1987 to 2000. During his tenure at the Royal Free he saw a large number of patients with serious infectious disease. A small minority of them remained unwell even after appropriate treatment and resolution of the acute symptoms of their infection. This was his first encounter with ME/CFS. At about this time he also met Dr Melvin Ramsay, one of the most important figures in the history of this condition. It enabled him to develop important insights into the nature of its underlying physical pathology. Subsequently, he established a clinic at the Royal Free dedicated to the care and management of patients with ME/CFS. This provided the basis for a number of academic studies which subsequently appeared in the medical literature. He was also a member of the Chief Medical Officer’s (of England and Wales) Working Group whose report on ME/CFS was published in January 2002. He was elected a Fellow of the Royal College of Physicians of London in 1993 and of Edinburgh in 1997.