Colin John Martin is an honorary senior clinical lecturer for the University of Glasgow and has carried out research in many aspects of radiation protection and radiation dosimetry. He has been a certified radiation protection adviser (RPA) since 1990 and has been an RPA2000 assessor since 2000. He is the vice-chair of ICRP Committee 3, and a member of several ICRP task groups, IAEA committees and UK working parties. He is also a member of the editorial boards for the Journal of Radiological Protection and Radiation Protection Dosimetry. David Temperton is a consultant clinical scientist and medical physics expert. He was head of RRPPS (University Hospitals Birmingham NHS Foundation Trust) from 1994 until his retirement in 2017. He acted as head of the RRPPS’s approved dosimetry service (ADS) which was the largest such service in the NHS. He was a certificated RPA, giving advice to clients in the healthcare, industrial and academic sectors. He was also an honorary lecturer at the University of Birmingham. Anthony Hughes studied medical physics at the University of Aberdeen, obtaining a PhD in 1990. For the next 13 years he worked as a clinical scientist in radiotherapy at Clatterbridge Hospital, and nuclear medicine at the Royal Liverpool Hospital. For the past 16 years he has been part of the regional physics service operated by Christie Medical Physics and Engineering, based at the Royal Preston Hospital. He has been an RPA since 2007 and an radioactive waste adviser (RWA) since 2011, specialising in nuclear medicine and PET. Tom Jupp achieved his MSc in medical physics in 2008. He completed clinical scientist training while working in the medical physics departments in the Royal United Hospital Foundation Trust in Bath and in Gloucestershire Hospitals NHS Foundation Trust, being awarded the Association of Clinical Scientists Certificate of Attainment in 2011. He has since worked in the radiation protection department at the Royal Surrey County Hospital NHS Foundation Trust as a medical physics expert and obtained RPA certification in 2018.