In the past, much of my work was on randomised trials of cancer screening. These included the Swedish Two-County Trial of breast cancer screening, on which the UK's national breast screening programme was based, the UK Trial of Flexible Sigmoidoscopy, and the UK Lung Screening Trial. AS a result of the breast screening work, I have twice been awarded the Alexander Margulis Prize for Scientific Excellence by the Radiological Society of North America.
Since 2010 I have been director of the Policy Research Unit in Cancer Awareness, Screening and Early Diagnosis, which is a collaboration of primary care physicians, behavioural scientists, epidemiologists and statisticians in seven institutions. It researches interventions to promote diagnosis of cancer at an earlier stage by both screening and symptomatic routes.