1. Cancer Research UK Promoting Early Presentation Group, Institute of Psychiatry, Kings College London, St Thomas' Hospital, London SE1 7EH, UK
2. NHS Cancer Screening Programmes, Fulwood House, Old Fulwood Road, Sheffield S10 3TH, UK
3. Health Behaviour Research Centre, Department of Epidemiology and Public Health, University College London, Gower Street, London WC1E 7HN, UK
4. Primary Care Education Research Group, Cancer Epidemiology Unit, Richard Doll Building, Oxford OX3 7LF, UK(Author now deceased)