Signals School 1941–1993, Leydene House, East Meon, near Portsmouth : Fire fighting training establishment 1946–1993, now part of HMS Excellent'' Military The Fortifications of Portsmouth were developed over several centuries to protect the fleet and dockyard from attacks either by land or by sea. From 1665 Bernard de Gomme oversaw construction of defensive Lines around both Portsmouth (the Dockyard and the old town) and Gosport (on the opposite side of Portsmouth Harbour). These defences were extended in the 18th century, before being superseded in the 19th by the Palmerston forts which encircle Portsmouth on and off-shore. These fortifications required substantial numbers of personnel to man them and, from the mid-18th century onwards, they (together with other troops who were either stationed in the garrison or preparing to embark overseas) were accommodated in a variety of barracks in and around the city. By 1900 these included: Cambridge Barracks, High Street (Infantry) – established in 1825 in a set of late-18th century warehouses; the officers' quarters have been occupied by Portsmouth Grammar School since 1926. Clarence Barracks (Royal Garrison Artillery) – established in 1760 as Fourhouse Barracks on land between St Nicholas Street and the fortifications (alongside an earlier Royal Marine Barracks); renamed in 1827; rebuilt around 1881, expanding across the old defensive lines into the field beyond; demolished c.1967. Colewort Barracks, St George's Road (Army Service Corps) – built as a garrison hospital, converted to barracks 1694, demolished to make way for expansion of nearby power station in the 1920s. Hilsea Barracks (Royal Field Artillery) – built 1854, Royal Army Ordnance Corps from 1921; closed 1962, site redeveloped for housing (the surviving 18th-century Gatcombe House served as the Officers' Mess). Milldam Barracks (Royal Engineers) – built late 18th century onwards, housed the Engineers responsible for upkeep of the fortifications; sold in 1969 and now occupied by the University of Portsmouth and Portsmouth Register Office. Point Barracks (Artillery) – built alongside the medieval Round Tower in 1846–50; sold to Portsmouth City Council in the early 1960s following disbandment of the UK's Coastal Artillery network. Part of the brick structure was demolished, but is marked by stones in the ground alongside the surviving casemates. St George Barracks, Gosport (Infantry) – built 1856–59 as a transit barracks for troops, continuing in military use until 1991; several buildings remain, since converted to new uses. Victoria Barracks (Infantry) – built in 1888 alongside New Clarence Barracks;