Petrie David
Sir David Petrie (1879–1961) was director general (DG) of MI5, the United Kingdom's internal security service, from 1941 to 1946. He was described as "a rugged and kindly Scot, with...immense physical and moral strength".
Petrie worked in the Indian Police between 1900 and 1936. His highest level in India was to chair the Indian Public Service Commission. In April 1941, he was appointed Director general of MI5. His task was to reorganize the service so that it could improve the efficiency. In the spring of 1946, Petrie retired.