communication links with the front line in France. During the Second World War, Britain's coastal defences depended on extensive barriers constructed along the shores, combined with large numbers of small defensive artillery positions supported by air cover. Several of the Device Forts were brought back into service in this way. Pendennis, St Catherine's, St Mawes and Walmer were equipped with naval gun batteries, Calshot and Hurst were rearmed with naval guns and anti-aircraft defences, and Sandsfoot was used as an anti-aircraft battery. Southsea continued in service, and was involved in Operation Grasp, which seized the French fleet in 1940. Others were used as support facilities; Yarmouth was requisitioned for military use; Portland was used for accommodation, offices and as an ordnance store, and West Cowes used as a naval headquarters for part of the D-Day landings. Camber was used as an early warning and decoy site to distract raids from nearby Rye. Early in the war a German bomber destroyed much of the captain's quarters at Deal, forcing William Birdwood to move to Hampton Court Palace. The Prime Minister, Winston Churchill, was appointed as the captain of Walmer Castle during the war, but declined to use it as a residence, noting that it was too expensive for him to maintain, and that it lay within the range of German artillery. 1946–21st century After the war, coastal defences became increasingly irrelevant as nuclear weapons came to dominate the battlefield. The remaining Device Forts still in military use were initially garrisoned with reservist units and then closed as military establishments. St Catherine's and Portland were decommissioned in the late 1940s, Hurst, Pendennis and Yarmouth in the 1950s, Southsea in 1960 and, after, the closure of its air base, Calshot followed in 1961. Widespread restoration work was then carried out; at Calshot, Deal, Hurst, Pendennis, Portland, St Catherine's and Southsea, the more modern additions to the fortifications were destroyed in an attempt to recreate the appearance of the castles at earlier periods of their history, ranging from the 16th to the 19th centuries. There was extensive research into the forts during this period, commencing in 1951 with a long-running research project commissioned by the Ministry of Works into the Device Forts, which in turn led to heightened academic interest in their histories during the 1980s. A range of the fortifications were opened to the public in the post-war years. Deal, Hurst, Pendennis and