Delan is a Professor of Global Child Health and an honorary consultant in Public Health in the Global Health division of Public Health England. He is co-director of the UCL Centre for the Health of Women, Children and Adolescents.

He qualified from the University of Manchester and then worked in clinical paediatrics in the UK and New Zealand. After completing a Diploma in Tropical Medicine and Hygiene, he worked with Medecins Sans Frontieres as a paediatrician in Pakistan (Kashmir earthquake), South Sudan (cholera outbreak) and Myanmar (post-cyclone Nargis). 

He was appointed as an NIHR Academic Clinical Fellow and then NIHR Academic Clinical Lecturer in Public Health in UCL. He completed a masters in public health at the London School of Hygiene and Tropical Medicine and a PhD from UCL, funded by a Wellcome Trust Research Training Fellowship. 

Delan is chair of ICHG, a special interest group of the Royal College of Paediatrics and Child Health. He was a commissioner and steering group member of the UCL-Lancet Commission on Migration and Health and is currently lead for child and adolescent health in Lancet Migration. He is the lead for the Lancet series on 'racism, xenophobia, discrimination and health' and is chair and founder of Race & Health and a member of The Lancet Group for Racial Equality (GRacE).