The Social and Environmental Determinants of Health programme will enable data from many different sources to be linked together to support research into understanding how different social and environmental factors affect our health and wellbeing, initially looking at childhood and ageing. With public involvement, it will develop the secure and trustworthy approaches needed to build up detailed pictures, whilst still preserving privacy, of how such factors affect individuals, their homes and households so that new approaches, services and policies can be developed to improve people's lives.