page_title: Device Forts
section_title: 1900–1945
hierarchical_section_title: Device Forts / Later history / 20th–21st centuries / 1900–1945
caption_attribution_description: English: Gun at Half Moon Battery Pendennis Castle
context_page_description: The Device Forts, also known as Henrician castles and blockhouses, were a series of artillery fortifications built to defend the coast of England and Wales by Henry VIII. Traditionally, the Crown had left coastal defences in the hands of local lords and communities but the threat of French and Spanish invasion led the King to issue an order, called a "device", for a major programme of work between 1539 and 1547. The fortifications ranged from large stone castles positioned to protect the Downs anchorage in Kent, to small blockhouses overlooking the entrance to Milford Haven in Pembrokeshire, and earthwork bulwarks along the Essex coast. Some forts operated independently, others were designed to be mutually reinforcing. The Device programme was hugely expensive, costing a total of £376,000; much of this was raised from the proceeds of the Dissolution of the Monasteries a few years before.
  These utilitarian fortifications were armed with artillery, intended to be used against enemy ships before they could land forces or attack ships lying in harbour.
context_section_description: By the start of the 20th century, developments in guns and armour had made most of the Device Forts that remained in service too small to be useful. Modern weapons systems and their supporting logistics facilities such as munitions stores could not fit within the 16th-century designs. A 1905 review of the Falmouth defences concluded that the naval artillery at St Mawes had become superfluous, as the necessary guns could be mounted at combination of Pendennis and newer sites along the coast, and the castle was disarmed. A review in 1913 concluded that keeping naval artillery at Calshot was also unnecessary, and the site was turned into an experimental seaplane station instead.
  Meanwhile, concerns had been growing about the unsympathetic treatment of historic military buildings by the War Office; for its part, the War Office was concerned that it might find itself financially supporting these properties from its own budget. Yarmouth Castle was passed to the Commissioners of Woods and Forests in 1901, with parts of it were leased to the neighbouring hotel. The War Office concluded that Walmer and Deal had no remaining military value and agreed to transfer the castles to the Office of Works in 1904, who opened both former fortifications to visitors. Portland Castle was placed onto what was known as the Schedule C list, which meant that the Army would continue to use and manage the historic property, but would receive advice on the suitability of repairs from the Office of Works.
  With the outbreak of the First World War, naval operations were mainly focused along the south-east and southern coasts. The defences of Pendennis were reinforced, while Southsea, with the addition of anti-Zeppelin guns, formed part of the Fortress Portsmouth plan for defending the Solent. Calshot formed a base for anti-submarine warfare, and the remaining castles of the Downs were used to support the activities of the Dover Patrol. St Mawes and Portland were used as barracks, and Walmer became a weekend retreat for the Prime Minister, Asquith, exploiting its good 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.
caption: 6-inch (152 mm) Mark 24 gun in the Half Moon Battery at Pendennis Castle, dating from the Second World War
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