Station sergeant (also known as crown sergeant or staff sergeant) is a police rank senior to sergeant and junior to inspector in some British and Commonwealth police forces. The rank insignia is usually a sergeant's three chevrons surmounted by a crown, or sometimes four chevrons. The Metropolitan Police (of London), which was the first force to introduce the rank, originally used four chevrons, but later changed to a crown over three chevrons, which was identical to the insignia worn by a staff sergeant in the British Army. A police officer holding the rank will be the senior sergeant in a police station, or in some cases the commander of a smaller sub-divisional police establishment. The rank is currently used in the Hong Kong Police Force (station sergeant), the Barbados Police Service (station sergeant), the Port of Felixstowe Police (station sergeant), and most Canadian police forces (staff sergeant). It was historically used in the London Metropolitan Police (station sergeant) and the Royal Parks Constabulary (crown sergeant). The rank is also used, though with a different operational role (see below), in the Australian Federal Police. Australia Although only used in special circumstances, the Australian Federal Police uniquely has separate ranks of both senior sergeant and staff sergeant. Whilst on deployment in peacekeeping operations with the International Deployment Group members of the AFP are appointed to the ranks of senior sergeant (three chevrons below a crown which is surrounded by a laurel leaf), station sergeant (a crown surrounded by a laurel leaf), superintendent (a pip and a crown), or commander (three pips and crown). Hong Kong In the Hong Kong Police Force, the rank of station sergeant (SSGT) is senior to sergeant but junior to inspector. A station sergeant is required to have served three years at the rank of sergeant and be recommended by a selection board before being promoted to the rank. Station sergeant is the highest non-commissioned rank in the Hong Kong Police Force. Because of that, station sergeants tend to be the most experienced NCO in a unit, serving as the commander or second-in-command of a unit and/or a station if necessary. To progress to the rank of inspector, a station sergeant must undergo the same application process as other junior officers. The rank badge of a station sergeant is the Hong Kong Police badge surrounded by a wreath worn in the centre of the shoulder strap. However, station