 From 1932, he prosecuted at the Central Criminal Court, until transferred to headquarters in 1938.Allan attained the rank of inspector in 1948, then superintendent in 1956, and was assistant to three police commissioners, William John MacKay, James Frederick Scott and Colin Delaney.In 1953, Allan was awarded the Coronation Medal, and in 1957 he earned the Queen’s Police Medal for Distinguished Service and the Police Long Service and Good Conduct Medal.