Cliffe Fort is on the banks of the River Thames near the village of Cliffe on the Hoo Penninsula.
It was built on the recommendations of the 1859 Royal commission.
It was constructed to prevent an enemy landing on the Hoo peninninsula to outflank the defences of Chatham,and also to work with nearby Shornmead fort and coalhouse fort (on the other side of the Thames in Essex)to prevent an enemy fleet continueing up the river Thames.
It was to be armed with 30 guns manned by 300 men.
During construction cracking and subsidence was encountered due to the marshland on which it was built.
Malaria mosquitoes was also another big problem for the builders and garrison.
The fort was proposed to be armed with 68 pdr Smooth Bore guns but this was then updated to the new 7" Rifled Muzzle Loaders on Moncrief carrages.
However,this was also dropped to the larger 12.5" Rifled Muzzle Loaders and then later also 11" Rifled Muzzle Loaders.
They were to be housed in the casemates protected by granite and shields made of teak.
In 1887 the armament was 2x 12.5" RML's and 9x11 RML's in the Casemates and 2x9" RML's in an open Battery.
In 1885 the experimental harbour defence system the Brennan Torpedo was installed at the fort,with two sets of launching rails.
This was the worlds first wire guided missile invented by the inventor Louis Brennan who also invented a monorail car and a prototype for the Helecoptor. The Brennan Torpedo was later replaced in favour of QF guns.
The sole surving Brennan Torpedo is on display at the Royal Engineers Museum at Gillingham.
In the late 19th century the fort was rearmed with 3x 31b QF guns in anti torpedo boat mode and in 1905 2 x 12 RML's. At the start of WWI 12x6" Breech Loader guns were transferred from Coalhouse fort to new open emplacements on the roof of the fort,these guns were later sent to France and replaced with 4" guns.
The fort stayed armed with light QF guns untill the end of WWII.
After the war it was sold to a local cement company.
Today the exterior of the fort can be seen from the Saxon Shore Way which runs around the outside of the fort.
Also the remains of one of the Launching rails for the Brennan Torpedo can still be seen.
The interior of the fort is off limits.
Inside the lower levels are flooded and parts of the fort are in a state of decay.
Brennan Torpedo launching rails remains.