Hammersley's education at Cambridge U was interrupted by war service spent in the Royal Artillery. Graduating in 1948, Hammersley joined the statistics faculty at Oxford U. In 1964 he was co-author of one of the first books on Monte Carlo methods. He was elected FRS in 1976.

http://www.statslab.cam.ac.uk/~grg/papers/ham1-ph.html Fuller biography and portrait.