In 1944 he moved to Birmingham University, joining Francis Simon's team in the Tube Alloys Project, the British programme to develop an atomic bomb. His PhD on isotope separation was completed in 1948. He then moved to the newly formed Atomic Energy Research Establishment at Harwell, where he continued to work on the separation of the isotopes of uranium, initially by gaseous diffusion and then using high speed centrifuges. In 1951 he moved to Capenhurst, where a large scale diffusion plant was being constructed. In two years, he was promoted to head of the Capenhurst laboratories, and then in 1958 he succeeded Leonard Rotherham as director of research and development of the industrial group of the United Kingdom Atomic Energy Authority.