John Yarnold is Emeritus Professor of Clinical Oncology, The Institute of Cancer Research, and formerly Honorary Consultant in Clinical Oncology at The Royal Marsden, London, UK. He led the first randomised clinical trial testing single fraction radiotherapy for patients with painful bone metastases plus 2 confirmatory studies co-led with Prof. Peter Hoskin and Prof. Pat Price. He has also been chief investigator of 8 randomised clinical trials testing new approaches to adjuvant radiotherapy for patients with early breast cancer, including moderate hypofractionation, the most recent trials being now led Professor Charlotte Coles and Professor Murray Brunt. A further 3 randomised trials tested hyperbaric oxygen and antioxidant therapies in the management of severe radiotherapy adverse effects. Several translational research projects were successfully linked to these clinical trials. Recognition of his contributions includes: Rohan Williams Medal, Royal College of Radiologists (UK), 1977; Honorary Life Member, Canadian Association of Radiation Oncology, 1996; Honorary Life Fellow, Royal Australasian College of Radiologists, 1999; The President’s Medal, The Royal College of Radiologists (UK), 2003; Klaus Breuer Medal, ESTRO, 2007; Honorary Life Member, Belgian Society for Radiation Oncology, 2008; Emmanuel Van de Scheuren Award Lecture, ESTRO, 2009; Fellow, European Academy of Cancer Scientists, 2011; George Edelstyn Memorial Lecture, National Cancer Research Institute, 2013; Jean H. Lubrano Distinguished Visiting Scholar, Dana Farba & Havard Cancer Institute, 2015; Lifetime Achievement Award, ESTRO, 2015; Fellow, Royal College of Physicians (UK), 2016; The Weiss Medal, Association for Radiation Research, 2017; Regaud Medal, ESTRO, 2021.