David Spiegelhalter is a statistician with a background is in Bayesian statistics. He jointly developed the Lauritzen-Spiegelhalter algorithm for exact evidence propagation in Bayesian networks, and then led the team behind the BUGS software for MCMC analysis of Bayesian models. He is now Chair of the Winton Centre for Risk and Evidence Communication in the University of Cambridge, which aims to improve the way that statistical evidence is used by health professionals, patients, lawyers and judges, media and policy-makers. He has over 200 refereed publications and is co-author of 6 textbooks, as well as The Norm Chronicles (with Michael Blastland), Sex by Numbers, and The Art of Statistics. He works extensively with the media, and presented the BBC4 documentaries ‘Tails you Win: the Science of Chance” and the award-winning “Climate Change by Numbers”. He was elected Fellow of the Royal Society in 2005, knighted in 2014 for services to medical statistics, and was President of the Royal Statistical Society for 2017-2018.