The article presents a new research agenda which links the composition of the British colonial administrations in the mid-20th century with the economic development of former colonies. It presents the first findings taken from the biographical records of over 14,000 senior colonial officers which served in 46 colonies between 1939 and 1966. Legal transplanting, i.e. the process of copying foreign law into countries lacking them, is discussed as a common practice in international development efforts and as new approach in understanding long-term economic development. The approach puts emphasis on the senior bureaucrats who are in charge of institutional copying. Successful transplanting requires very specific training and personal experience in the receiving society. Colonial officers with such characteristics served in the British colonial administrations while decolonization provides a historic period of intensified legal and institutional transplanting.