John Gilbert Presslie Barnes is a British computer scientist best known for his role in developing and publicising the Ada programming language.Barnes studied mathematics at Cambridge University and later worked at Imperial Chemical Industries. He was an industrial fellow at Wolfson College, Oxford in the very late 1970s or early 1980s, most likely at the suggestion of Prof. C. A. R. Hoare.Prior to working on the Ada design team he designed and implemented the programming language RTL/2.