hands. In two forts, Fort Darnet and Fort Hoo, the casemates formed a complete circle; other circular works were built as sea forts with foundations on the sea-bed and entirely surrounded by water. A number of the Royal Commission coastal works were upgrades of existing fortifications, such as the 16th century Pendennis Castle at Falmouth. Land forts The landward fortifications were intended to prevent an enemy force who may have landed at an undefended beach from marching overland and assaulting a dockyard from the rear, or simply bombarding it. These forts were built in the new polygonal style without the traditional bastions and generally sited so as to form a "ring fortress", so that each fort could support its neighbour with artillery fire. Construction of some landward forts at Portsmouth and Plymouth had already begun in the 1850s and work on the ring fortress at Chatham was not started until 1875, resulting in very different designs as military theories changed over the decades. Gallery See also Palmerston Forts London Defence Positions Royal Commission References Bibliography Crick, Timothy (2012) Ramparts of Empire: The Fortications of Sir William Jervois, Royal Engineer 1821-1897, University of Exeter Press, Hogg, Ian V (1974), Coast Defences of England and Wales, 1856-1956, David & Charles, Moore, David (1990), Fort Brockhurst and the Gomer-Elson Forts (Solent Papers; No. 6.), David Moore, Dyer, Nick (2003), British Fortification in the late 19th and early 20th Centuries, The Palmerston Forts Society, External links Palmerston Forts Society Royal Commission; victorianforts.co.uk REPORT OF THE COMMISSIONERS APPOINTED TO CONSIDER THE DEFENCES OF THE UNITED KINGDOM (full text); victorianforts.co.uk British defence policymaking Invasions of the United Kingdom Defence 1859 in the United Kingdom 1860 in the United Kingdom 19th-century military history of the United Kingdom 1859 establishments in the United Kingdom