Battery of 563 Coast Regiment. The castle operated as a Battery Operating Post—one of the first-floor rooms in the keep became the Battery Office—and provided accommodation. Following Birdwood's death, in 1951, the castle officially ceased to function as a residence and was passed to the Ministry of Public Buildings and Works. Restoration work was carried out during the 1950s, largely removing the remaining 18th-century modifications on the seaward side of the castle. In 1972 the captaincy of Deal Castle (in abeyance since 1951) was revived, as an honorary appointment, and vested in General Sir Norman Tailyour; he was succeeded in 1979 by Major General Ian Harrison. Since the latter's death, in 2008, the captaincy has been held ex officio by the Commandant General Royal Marines. In the 21st century, Deal Castle is operated by English Heritage as a tourist attraction, receiving 25,256 visitors in 2008. It is protected under UK law as a scheduled monument. Architecture Deal Castle retains most of its original 16th-century structure, including a tall keep with six semi-circular bastions, across, at the centre, flanked by a further six rounded bastions, the western of which served as a gatehouse, surrounded by a moat and a curtain wall. The castle's bastion walls are thick. It was constructed using Kentish ragstone from near Maidstone, locally made bricks and Caen stone recycled from local monasteries. It was larger than its sister castles at Walmer and Sandown, measuring approximately across and covering . The castle originally had four tiers of artillery – the heaviest and longest-range weapons occupying the upper levels, including the keep – with a total of 66 firing positions and another 53 gunloops in the basement for handguns, should close defence be required. The embrasures in the walls were all widely splayed to provide the maximum possible space for the guns to operate and traverse, and the interior of the castle was designed with vents to allow the smoke from its guns to escape. The battlements on the modern castle are in a faux medieval, rather than Tudor, style and date from 1732. The historian John Hale considered the original castle to form a transitional design between older medieval English designs and the newer Italian styles of defence. Like its sister castles along the Downs, Deal suffered from design problems: it needed too many guns to ever be fully equipped; its curved surfaces were vulnerable to attack; and