1. Division of Epidemiology and Public Health, University of Nottingham, Nottingham, UK
2. Addiction Research Group, Norwich Medical School, University of East Anglia, Norwich, UK
3. Institute of Social Marketing and Health, University of Stirling, Stirling and Population Health Research Institute, St George’s, University of London, London, UK
4. Alex Bobak, GP Specialist in Smoking Cessation, Wandsworth Medical Centre, London, UK
5. Division of Primary Care, School of Medicine, University of Nottingham, University Park, Nottingham, UK