1. School of Health Sciences, University of East Anglia, Norwich, NR4 7TJ, UK
2. Division of Primary Care, UK Centre for Tobacco and Alcohol Studies and National Institute for Health Research School for Primary Care Research, University of Nottingham, Nottingham, UK
3. Division of Epidemiology and Public Health, University of Nottingham, Nottingham, UK
4. Department of Primary Care and Public Health, Imperial College London, London, UK
5. Behavioural Science Group, Institute of Public Health, University of Cambridge, CB2 0SR, UK
6. Population Health Research Institute, St Georges, University of London, London, UK
7. Institute for Social Marketing and Health, University of Stirling, Stirling, UK