1. Clinical Trial Service Unit and
2. Cancer Epidemiology Unit, University of Oxford, Oxford;
3. Haemophilia Centre, Churchill Hospital, Oxford;
4. Department of Haematology, Birmingham Children's Hospital National Health Service Trust, Birmingham;
5. Department of Haematology, Manchester Royal Infirmary, Manchester;
6. Haemophilia Centre, Royal Free Hospital, London;
7. Haemophilia Centre, Edinburgh Royal Infirmary, Edinburgh, United Kingdom