Professor Harrison is the National Police Chief Medical Officer based in the National Police Wellbeing Service (NPWS)/ College of Policing. Between 2014 and 2021 he was Chief Medical Officer for Devon and Cornwall police and strategic health and wellbeing lead for the Alliance with Dorset Police. He was Clinical Director of Organisational Health and Wellbeing at Imperial College Healthcare NHS Trust (2003 – 2014) and Senior Lecturer in Occupational Medicine / Consultant Occupational Physician at the University of Newcastle-Upon-Tyne (1990 – 2003). He has held positions as Director NHS Plus/advisor to the Health and Work team of the Department of Health and Head of the National School for Occupational Health of England and Wales. He is an Associate Professor at Brunel University in clinical organisational development. Previously he was Academic Dean of the Faculty of Occupational Medicine, a board member of ICOH and a past Chairman of EASOM.