A Protestant and Freemason, Allan joined the NSW Police Force in 1929, posted at Redfern. 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. He was also specially commended by the State Premier Robert Askin for devotion to duty and exceptional skill and ability in connection with the conviction of Stephen Leslie Bradley for the murder of Graeme Thorne. Allan was acting deputy-commissioner in 1959 and became Chief Commissioner of Police on 28 February 1962. Known unofficially as "Norman the Foreman," Allan finished his tenure during the years Robert Askin was Premier of New South Wales. While Allan was Police Commissioner illegal casinos in Sydney flourished in full view of both police and the public and yet very few police raids ever took place. The collective annual turn over of these casinos was estimated in 1974 to be $600 million. This netted the operators an untaxed profit of $16 million after all costs and alleged bribes had been paid off. A close associate of Perc Galea claimed that Police Commissioner Allan and his successor Frederick Hanson were paid $100,000 a year each in bribes. One of the greatest challenges of his tenure as commissioner was the Arantz scandal. Detective Sergeant Phillip Arantz developed a computer program that gave accurate crime data and showed information previously published by the commissioner was misleading or incorrect. NSW Police refused to acknowledge the new data, which led Arantz to leak it to the press in November 1971. Following this he was forcibly admitted into hospital having been declared mentally ill by a police doctor, who later claimed he had been coerced into doing so by senior police, and in 1972 Arantz was sacked from the force. Allan at first denied the new figures were accurate but later confirmed their validity in a report tabled to parliament in September 1972. Arantz was finally reinstated back into the police force in 1989 after the NSW parliament brought in new reinstatement legislation. In July 2008 Penguin published the book Gentle Satan: Abe Saffron, My Father by Alan Saffron, the only son of reputed Sydney crime czar Abe Saffron. The book contains allegations about Allan's supposed corrupt relationship with Saffron, claiming that Saffron regularly paid both Allan and Askin bribes of between A$5,000 and $10,000 per week each, that Allan was a frequent visitor to Saffron's office and home. Also included in the book is the allegation that Saffron paid for an overseas trip for Allan and an unnamed female companion.
