Professor Anne Johnson is Professor of Epidemiology and Director of the Centre of Infectious Disease Epidemiology at University College London. She is known internationally for her groundbreaking work on the epidemiology of HIV infection and the study of sexual lifestyles and risk behaviour. She has led important randomised control trials of behavioural interventions to promote sexual health. She is leading the second national survey of sexual attitudes and lifestyles which will map changes in behaviour following the HIV epidemic.