Sir Roy is Professor of Infectious Disease Epidemiology in the School of Public Health, Faculty of Medicine, Imperial College London and Director of the Centre for Neglected Tropical Disease Research. His recent appointments include Rector of Imperial College London and Chief Scientist at the Ministry of Defence, UK. His research interests are in interdisciplinary studies at the interface between medicine, biology, mathematics and computation.

Sir Roy has also served as Director of the Wellcome Centre for Parasite Infections from 1989 to 1993 (at Imperial College London) and as Director of the Wellcome Centre for the Epidemiology of Infectious Disease from 1993 to 2000 (at the University of Oxford). He is the author of over 450 scientific articles and has sat on numerous government and international agency committees advising on public health and disease control including the World Health Organisation, Bill and Melinda Gates Foundation and UNAIDS. From 1991-2000 he was a Governor of the Wellcome Trust.