Donald Watts Davies (1924-2000), British computer scientist. Davies studied physics at Imperial College, London, working on the British nuclear weapons program, then obtaining a degree in mathematics. From 1947 he worked at the National Physical Laboratory (NPL) on early computers such as Pilot ACE. His most famous work was in the 1960s and 1970s on packet switching, a vital part of the communications technology of the internet. Davies, who retired in 1984, also worked on smart cards and network security. He was made CBE in 1983, and a Fellow of the Royal Society in 1987. Photographed in 1974.