Initial plans for the construction of the fort included thirteen guns upon the terreplein protected by shields, three guns on barbette mounts and two for land defence with twenty guns within the granite faced casemates protected by iron shields. The thirteen guns to be installed upon the terreplein were dropped due to trouble with construction. The site of the fort was to be on marshy ground and it has been written that conditions could be injurious to the health of the officers supervising the construction.
In 1855 building work commenced to convert one of the 9" magazines into a Brennan Torpedo Station, the Brennan Torpedo was introduced at the fort in 1890. The torpedo was a wire-guided harbour defence missile that was launched from the station via launching rails.
Cliffe Fort as it is today
In 1861 gravel was found at a depth of sixty feet and chalk at seventy-nine feet. The fort required thirty-foot long piles but still encountered problems. Reports from 1865 showed difficulties including subsidence and cracking. The fort, when complete, was much smaller than planned with only ten guns within the casemates. Underneath the casemates were two parallel tunnels, one a passage connecting the shell and cartridge stores and the other a lighting passage. The lighting passage was a narrow tunnel and had many offshoots with steps leading up to light recesses within the walls of the main tunnel. You could also find these light recesses within the walls of the shell and cartridge stores, the recesses were constructed to prevent explosive material coming into contact with the naked flame of the lamp, this was placed within the recess and would be protected by a glass front and a glass door behind giving access from the lighting tunnel. A dry ditch and earthworks on the seaward side further protected the fort; it was built for a compliment of 300 men although, apart from troops from various regiments involved on gun drill or on exercises, it was normally manned by a much smaller garrison.
Armament of the fort in 1887 consisted of two 12.5" RMLs, six 11" RMLs. both types within the casemates and two 9" RMLs in the open battery. In 1855 building work commenced to convert one of the 9" magazines into a Brennan Torpedo Station, the Brennan Torpedo was introduced at the fort in 1890. The torpedo was a wire-guided harbour defence missile that was launched from the station via launching rails. In 1895 the armament consisted of two 12.5" RMLs, five 11" RMLs, one 9" RML in the open Battery, three 3pdr QF guns in new concrete emplacements on the roof and the Brennan Torpedo. The armament was further updated in 1899 to four 4pdr QF guns and again later to either two 4.7" guns or 6" guns. During the Second World War the fort was armed with two 4" BL guns for the use against enemy aircraft. Many other guns were mounted within and on the fort during its time in service.
During the Second World War the fort was armed with two 4" BL guns for the use against enemy aircraft. Many other guns were mounted within and on the fort during its time in service.
As an additional defence, provision was made to flood the marshes with river water by breaching the flood defence walls. This was to create an obstacle to the movement of an enemy landing force attempting to advance inland. By the later 1880s, the ditch of the fort had been infilled. This was to provide a further thickness of protection against incoming shells for the magazines, whose front wall was the escarp of the ditch.
Probably the most interesting aspect of Cliffe Fort today is the remains of an experimental ‘fire by wire’ Brennan Torpedo system – the remains of the launching rails are still visible today.
Brennan Tordeo Rails
Today Cliffe Fort shows signs of neglect and has seriously deteriorated over the past few years and the Scheduled Monument is now badly flooded, the parade ground is under at least one foot of water with the magazines, access tunnels and lighting tunnels under at least two feet of water. Standing derelict many features remain at the fort, including gun rings, rails and other features within the casemates, gun emplacements, observation posts and shelters upon the roof, two Brennan Torpedo launching rails leading into the river and the retractable observation post for the torpedo. Although access is possible it is not easy and is very dangerous: it is strongly advised that no attempt should be made to enter the site! It is also on private property and all access is denied. Inside there are many hidden dangers including a deep well that is hidden by the flooding water inside and crumbling roofs, floors and walls that may not hold a person’s weight.
Cliffe Fort, is privately owned, and lies in an area that is use commercially, and this involves the use of machinery and heavy moving plant. There are number of additional significant monuments in the area, included the Lime Kilns and Romano-British cremation and burial site. The fort lies within the area of The Thames Estuary and Mashes SPA and is a designated RAMSAR estuary and wetland, and there is the RSPB Cliffe Pools reserve adjacent to the site.
Cliffe Fort, Hoo Peninsula, Kent:
Survey and Analysis of the 19th-Century Coastal Artillery Fort
In 2010 the former English Heritage Archaeological Survey and Investigation team undertook a detailed survey of Cliffe Fort, a coastal artillery fort built in the 1860s. The fort is located on the Hoo Peninsula, Medway, in the parish of Cliffe and Cliffe Woods, on the south side of the Thames. It is 3 km west of Cliffe village in the area of the former cement works. The fort is a Scheduled Monument and is on the Heritage at Risk register, where, due to flooding, vandalism and partial collapse, the condition of the structure is described as ‘very bad’. The fort has had little previous investigation and was identified as needing detailed research by the Hoo Peninsula Historic Landscape Project, a multidisciplinary landscape project which aimed to increase our knowledge and understanding of the peninsula in order to contribute to strategic decision-making. The survey results will inform the future management of the site and provide an enhanced designation base. Cliffe Fort was part of a large and expensive defence infrastructure programme undertaken in the 1860s and incorporated the latest in fortification theory and technology. It was one of the last casemated forts with iron shields to be completed. Investigation revealed that despite some almost immediate alterations to the basement magazines, a lack of alteration in the 20th century has preserved a number of areas in the fort that reflect its late 19th century use. Later adaptations for rooftop guns reflect the changing nature of conflict through the 20th century. Research has also revealed that the fort contains one of the best preserved of the rare Brennan torpedo installations, including the remains of a unique rising observation tower. This report was published in 2017.
The report, which in itself is excellent and covers far more that can be reproduced on our webpages, can be downloaded as four separate PDF's directly from Historic England's website at:
More can be found in the following:
V. Smith in Defending London's River, The Story of the Thames Forts.
Ian V Hogg, Coastal Defences in England and Wales 1586 – 1956, Newton Abbot, 1977
J.D. Wilson, Later Nineteenth Century Defences of the Thames, Journal of the Society for Army Historical Research, XII. 1963
A.D. Saunders, Tilbury Fort and the Development of Artillery Fortifications in the Thames Estuary, Antiquaries Journal, XL 1960
The National Archives, Kew