The paper is concerned with the decade and a half spent by the development economist, Arthur Lewis, at the London School of Economics between 1933 and 1948. It discusses the intellectual traditions of the institution that Lewis joined, and the various influences on the young economist. His research and teaching roles in London and Cambridge are covered, together with his work for the Fabian Society, and his links with the anti-imperialist movements centred in London in the 1930s and 1940s. The aim of the paper is to shed light on this highly significant but little known period in the career of the foremost development economist.