Drop Redoubt is located on the Western Heights in Dover, Kent. The redoubt is the eastern most fort set in a complex of fortifications on the western escarpment which provided protection to the town and harbour from landward attack as well as from seaward bombardment. A redoubt is a defensive building where soldiers can hide while fighting.
Originally on the Western Heights the Romans built a pharos, a lighthouse, which was one of a pair, the other one was built on the opposite escarpment which is now in the grounds of Dover castle, and they date to around the 1st or 2nd century AD. This pharos on the western escarpment stood until the 17th century but it gradually fell apart. It was known as Bredenstone and Caesar's Altar in the 16th and 17th century and Devil's Drop in the 18th century. A concrete slab and two flint walls mark the location of the pharos.
The first fort was just a simple pentagon. Trenches were cut into the hillside and faced with brick. It contained a barracks, artillery and a magazine and was designed to hold up to 200 men. The men would have stayed in five bomb proof rooms covered in a thick layer of earth and were known as casements.
With the increasing threat of invasion during the 1850's due to Napoleon III's military campaigns Drop Redoubt was expanded. Caponiers, were added to the four corners inside the ditch, to provide gun fire into the ditch so the enemy could not gain a foot hold close to the walls of the redoubt, also gunrooms were built alongside two of them to allow fire along the North and South-East Lines. The magazine was enlarged and officers quarters were built, a guardroom with cells was also added. Drop Redoubt was to be equipped with twelve smooth bore 24 pounder guns but many were not installed because the Napoleonic wars were almost at an end by the time the redoubt was completed. It is listed that only three of the 24 pounder guns were in place alongside six 12 pounder saluting guns and an 8" mortar.
The redoubt was utilised early in the Second World War as an artillery observation post and later a squad of commandos were housed in two of the caponiers so that in the event of invasion, they would have been responsible for destroying Dover Harbour. Their presence was secret and the lines around the Redoubt were mined.
The Drop Redoubt was surveyed by the Royal Commission on the Historical Monuments of England as part of the Dover Western Heights Survey project, between 1998 and 2000.