After Clare College, Cambridge, the London Hospital Medical School, and 3 years of postgraduate education, he departed for Jamaica in August 1996 to work in the Department of Medicine, University Hospital of the West Indies, Kingston. He collaborated with Dr. Paul Milner in the Sickle Cell Clinic and was funded by the Wellcome Trust for sickle cell research from 1967-1971. In late 1971, he joined the MRC Abnormal Haemoglobin Unit, Cambridge and in late 1972 returned to Jamaica to work at the MRC Epidemiological Research Unit at the University of the West Indies. From 1973-1981 he established the Cohort Study based on all cases detected during the screening of 100,000 consecutive births. From 1974-1999, he directed the MRC Laboratories at the University of the West Indies continuing studies in the natural history of sickle cell disease. In 1986 the Sickle Cell Trust (Jamaica) was formed as a locally registered charity to raise funds to build a dedicated Sickle Cell Clinic (1987-1988) and the Education Centre for Sickle Cell Disease (1994). Since retiring from the MRC Laboratories in 1999, he continued as Chairman of the Sickle cell Trust developing public education programmes in sickle cell disease among Jamaican secondary schools. From 2007, started the Manchester Project in central Jamaica to determine whether the identification of haemoglobin genotypes among senior school children with counselling of carriers will reduce births with sickle cell disease. For the last 30 years, he has collaborated with colleagues on the development of sickle cell services and research in Brazil, Europe, African countries, the Arabian Gulf and India.