Peter studied medicine at KCL and Westminster Medical School. He practised hospital medicine for three years before tasting psychiatry at the Maudsley Hospital and Institute of Psychiatry where he remained for nine years becoming an honorary consultant and senior lecturer; three of these were spent as an MRC Training Fellow and reading Epidemiology at the London School of Hygiene and Tropical Medicine. He was seconded half-time to the Department of Health 1993-1996 where he led the Policy Research Programme Mental Health Research Initiative and convened the multi-party group that led to the reduction in paracetamol pack size as part of the national suicide prevention policy.
After five years at the University of Nottingham, four as Professor of Psychiatry and Community Mental Health, Peter moved to Cambridge in 2000 as Head of Department of Psychiatry and honorary consultant psychiatrist with the Cambridgeshire & Peterborough NHS Foundation Trust.; he was co-founder of the award-winning Cameo early intervention team for young people who experience a first episode of psychosis. In 2014 he stepped-down as Head of Department to become Deputy Head of the School of Clinical Medicine.
Peter was elected a Fellow of Wolfson College in 2003. He is a Director of Cambridge University Health Partners, and Director of the National Institute of Health Research (NIHR) Collaboration for Leadership in Applied Health Research & Care for the East of England (CLAHRC EoE). He is a trustee of MQ: transforming mental health, a research charity endowed by the Wellcome Trust, and is an NIHR Senior Investigator Emeritus. Peter has been President of IEPA Early Intervention in Mental Health 2016-2018.