ropeanProspective Investigation into Cancer-Norfolk; ICD 10: the 10th Revision of the International Classification of Diseases; NHS: National Health Service; ONS: Office of National Statistics; PPV: Positive Predictive Value; TIA: Transient Ischaemic Attack; WHO: World Health Organisation.Competing interestsThe authors declare that they have no competing interests.Authors' contributionsKTK is a pr