Lewis trained in medicine at the University of Cambridge and holds a Master’s degree in Public Health from the London School of Hygiene and Tropical Medicine. He began his career in acute and emergency medicine, working at hospitals in the UK and Australia over an 11-year period. After completing his higher specialist training in public health medicine, he was appointed Senior Fellow of the Nuffield Trust (an independent health policy think-tank), then as senior director for clinical outcomes and analytics at Walgreens in Chicago, before returning to the UK to take up his current post. A fellow of both the Royal College of Physicians of London and the UK Faculty of Public Health, Lewis is the lead author of the postgraduate textbook, “Mastering public health”, and has published over 40 peer-reviewed articles. In 2008, he was the overall winner of The Guardian Newspaper’s public service awards. In 2011, he was awarded the Bradshaw Lectureship of the Royal College of Physicians of London. More recently, he has served as an external adviser to the World Bank and he leads the care model design work-stream of NHS England’s new care models programme.