service numbers as a temporary measure and was revoked in the 1990s. The new Service Number used a random alphabetic letter and 8 numbers in the same format as SINs to avoid changing service forms. Hong Kong Current officers of the Hong Kong Police use a 5 digit number and are worn by all ranks below senior officers. The same numbering pattern is used by the Hong Kong Correctional Services and the Hong Kong Fire Services. United Kingdom Soldiers in the British Army are given an eight-digit number, e.g. 25232301. Prior to 1920, each regiment issued their own service numbers which were unique only within that regiment, so the same number could be issued many times in different regiments. When a serviceman moved, he would be given a new service number by his new regiment. Commissioned officers did not have service numbers until 1920. The modern system was introduced by Army Order 338 in August 1920. Numbers were then a maximum of seven digits, later groups of numbers up to eight digits were added. Until 1960, National Servicemen who voluntarily remained in the Armed Forces continued to use their National Service numbers. Until 2007 and the introduction of the Joint Personnel Administration (JPA) system, Army Officers were issued with a six-digit Personal Number, as opposed to the eight-digit Army Number for enlisted personnel. Newly commissioned officers now receive an eight-digit service number, but six-digit Officers' Personal Numbers issued prior to the introduction of JPA remained unchanged. In the Royal Navy, prior to the introduction of JPA, service numbers were also of eight digits but began and ended with a letter, depending initially on the depot where the sailor was recruited. The first letter designators were: P (Portsmouth), C (Chatham), and D (Devonport), with the final letter being a checksum. Later, the designators were reassigned and were used to distinguish between men and women within the Royal Navy as well as to distinguish between officers and ratings. A service number beginning with D designated a Royal Navy male rating, W a Royal Navy female rating, C male officers, and V female officers. P designated a Royal Marines other rank, while N a Royal Marine officer. Following the introduction of JPA, all newly issued Royal Navy service numbers became an eight-digit number format beginning with 3, with no distinction made between male, female, ratings, officers, and Royal Marines. United States The Armed