Sub-inspector (SI), or sub-inspector of police, is a rank used extensively in South Asia: in the police forces of Bangladesh, Pakistan, India, and Sri Lanka, which is primarily based on the British model. It was formerly used in most British colonial police forces and in certain British police forces as well. The rank usually was in charge of a police substation or assisted an inspector. United Kingdom The rank of sub-inspector was introduced into the Metropolitan Police in the late 19th century. It did not last long, being effectively replaced by station sergeant in 1890. Officers who already held the rank retained it, and were promoted to inspector as soon as a vacancy arose. In the Metropolitan Police, a rank wearing one star was formerly officially known as a "station inspector" to distinguish it from the more senior rank of sub-divisional inspector that was abolished in 1949. Canada The Royal Canadian Mounted Police rank of sub-inspector was introduced in 1942 with the insignia of one star, similar to an army second lieutenant. This was changed in 1960 to three stars, similar to an army captain. It was disestablished in the reorganization of 1990, which eliminated the RCMP's subaltern ranks. Hong Kong The rank of sub-inspector was eliminated in 1970.<ref>p.32 Gaylord, Mark S. & Traver, Harold ;;Introduction to the Hong Kong Criminal Justice System Hong Kong University Press, 1 June 1994 -</ref> British South Africa Police The rank of sub inspector was replaced after the Rhodesian Unilateral Declaration of Independence with three grades of; patrol officer, senior patrol officer and section officer with one, two, and three gold coloured bars respectively. India A sub-inspector (SI) is generally in command of few police personnel (with head constables, the equivalent of corporals, commanding police outposts). It is the lowest rank of officer who, under Indian Police rules and regulations, can file a charge sheet in court, and is usually the first investigating officer. Officers subordinate to them cannot file charge sheets, but can only investigate cases on their behalf. They can be station officers in some states, like Kerala. A sub-inspector ranks above an assistant sub-inspector of police (ASI) and below an inspector. Most sub-inspectors are directly recruited into the police and have better educational qualifications than lower-ranking police officers. Specialised units such as the Central Armed Police Forces, State Armed Reserve Police and Armed Battalions use the same rank, but generally these