After serving as Director of the Department of Maternal, Child and Adolescent Health, WHO Geneva, Professor Anthony Costello returned to University College London in June 2018 as Professor of Global Health and Sustainable Development. Trained in paediatrics, he led the first Lancet Commission on Climate and Health published in 2009 with the strapline “Climate change is the biggest global health threat of the 21st century”. In 2015 he conceived and set up the international Lancet Countdown for Climate and Health Action of which he is chair. He is also founder and senior adviser to the Children in All Policies 2030 programme supported by WHO, UNICEF and the Lancet. He was an also co-founder of Independent SAGE which aims to bring a greater focus on public health, transparency and public engagement to the UK Covid response.