He stayed at Manchester as an assistant lecturer for two years before taking a post as a lecturer at the Bristol University Fruit and Vegetable Preservation Research Station (1948–50) followed by one as a senior scientific officer at the Hannah Dairy Research Institute, Ayr (1950–53).[3]
A succession of other appointments followed: senior scientific officer at Christie Hospital, Manchester (1953–55), head of the Biochemistry Department at the Animal Virus Research Institute, Pirbright (now the Institute for Animal Health) (1955–83) (deputy director (1980–83)) and head of the Virology Department at Wellcome Biotechnology Laboratories, Beckenham {1983-90}. He was also appointed professorial fellow at Queen's University, Belfast (1986–2004) and professor of microbiology at Surrey University (1989–90) and adjunct professor, School of Epidemiology and Public Health, Yale University (1990–2004). He was a visiting scientist at the US Department of Agriculture Plum Island Animal Disease Center, New York (1995–2004) and a consultant with the US Department of Agriculture (1990–2004).[4] Most of his efforts were directed towards the study of animal diseases such as foot-and-mouth disease and rabies.
He undertook substantial committee work. He was a member of an international committee on the taxonomy of viruses (1968–1981) (president (1981–1987)), chairman of the comparative virology programme run by WHO and UN, scientific secretary for the International Association of Biological Standardisation (1980); chairman of the Royal Society Biological Education Committee (1983–1987), member of the Spongiform Encephalopathy Advisory Committee (1990–1998) and honorary member of the Society for General Microbiology (1991). He was also member of council and editor-in-chief of the Journal of General Virology (1975–1980) and took part in the Royal Society Infectious Diseases in Livestock Enquiry.[4]