William George Penney, Baron Penney, OM, KBE, FRS, FRSE[3] (24 June 1909 – 3 March 1991) was an English mathematician and professor of mathematical physics at the Imperial College London and later the rector of Imperial College. He had a leading role in the development of Britain's nuclear programme, a clandestine programme started in 1942 during World War II which produced the first British atomic bomb in 1952.[4]