Coalhouse Fort Coalhouse Fort is a large casemate d fort in East Tilbury , near the modern town of Tilbury , in Thurrock , Essex , downstream from Tilbury Fort . It contains a museum of memorabilia from World War I and II . History . Coalhouse Point was the site of an artillery battery , although nothing survives of this building . The fort was rebuilt in the 1860s following recommendations by the Royal Commission on the Defence of the United Kingdom as a coastal defence and was completed in 1874 by General Gordon . . The fort was built on low lying land in a curve of the river Thames at East Tilbury and was positioned there to form a " triangle of fire " between Coalhouse Fort on the Essex bank of the river and Cliffe Fort and Shornmead Fort on the Kent bank . It continued to serve as a defence to the capital through two world wars and was eventually bought by Thurrock Council in 1962 . During World War Two , rooms in Coalhouse Fort were equipped with instruments used to monitor the magnetic field of ships as they left the docks at Tilbury . This monitoring was to confirm the effectiveness of the individual vessel ' s degaussing equipment . Degaussing is a process whereby the naturally occurring magnetic field of a steel hulled ship could be neutralised by fitting electrical cables around the hull and passing an electric current through them . The neutralisation of the magnetic field was used as a countermeasure against magnetic mines , which as the name suggests , are triggered by the magnetic field of a ship ' s hull passing over them . The monitoring station was staffed by Wrens ( Women ' s Royal Naval Service ) working with civilian technicians . Cables were laid on the river bed and as ships passed over them , the magnetic field could be measured and ( if necessary ) adjustments made to the ship ' s equipment . The fort communicated with the ships by flags , Aldis lamp and in some cases by launch if the ship failed to stop . The Wrens and the technical staff were under strict orders not to discuss their work as degaussing was highly secret . Armament . When completed in 1874 , a single tier of armoured casemates and an open battery housed 20 rifled muzzle loading guns of 9 , 11 and 12 . 5 - inch calibre . By 1906 , these were obsolete and were replaced by breech loading 6 - inch and 12 pounder quick firing guns . These served through World War I but were all removed by the 1930s . In May 1940 , the 5 . 5 - inch guns were removed from HMS Hood in a refit . A pair of these were installed in specially built casemates on the roof of the fort . The fort and nearby buildings . Coalhouse Fort itself is partly surrounded by a water filled " wet ditch " ( not moat ) and a dry ditch as part of the defences from the Victorian period . Apart from wells and a water storage cistern , there are no underground structures at Coalhouse , ( although there are tunnels running beneath it within its perimeter wall ) . As the fort is built on marshland , any excavations would be likely to fill with water . Due south from the fort and close to the river is the remains of a quick firing battery . This was constructed in the early part of the twentieth century and originally equipped with 12 pounder artillery pieces . Further on down the river , at some distance from the fort , there are a number of defensive works . On the river foreshore about half a mile from the fort stands the remains of an early radar tower . This tower was constructed during World War II and was one of the earliest examples of its type . Because of the secrecy surrounding radar during World War II this structure was marked on maps as a ' water tower ' to confuse the enemy and this ' decoy ' name has been continued on maps up until recently . In 1949 , the fort was leased to the Bata Shoe Company for storage and was purchased from the government in 1962 by Thurrock Council . The surrounding land was cleared and turned into a public park but the fort was kept closed . As part of the Tilbury Riverside project , a pathway has been developed between Coalhouse and Tilbury Fort passing along the river bank and past Tilbury Power Station . This is known as the Two Forts Way . The path is just over three miles and is described as " a challenging route suitable for able bodied walkers and experienced cyclists . " Current status . In 1983 the fort was leased to voluntary group the Coalhouse Fort Project which aims to save the building from dereliction . Currently the Project is applying for various grants . More money for the fort will also mean it is able to stay open longer . The ultimate goal for the project is to restore the building as close as possible to its original condition . Currently the fort is open for about 18 days during the year but special group visits can be arranged . The fort holds a series of open days throughout the year and also has special events days . During its recent history the fort has been used as a location for TV programmes and films . These include the external shots of the prison at the beginning of " Batman Begins " . Gatehouse redevelopment . In 2007 , a grant was given to Coalhouse Fort by English Heritage and Thurrock Borough Council amounting to £125 , 000 to redevelop the gatehouse . The Projects plans for this block range from an interpretation room to a small shop . Work began on restoration in early 2009 . Park Trail . In June 2011 , two interactive trails were launched as an iPhone app known as Thurrock Mobile Explorer . These describe two routes around the park and provide information about the history and environment at numbered points . Haunting . Although the fort was built between 1861 – 74 , quite some time after neighbouring Tilbury Fort , which was built in the 16th Century for Henry VIII . Roman remains , dating from AD 43 or shortly after , have been found in East Tilbury , and at some point during AD 600 St . Cedd erected a church in the area . The site saw action in both world wars before being brought by the local council , Thurrock Council in 1962 . Loud sighs and the sounds of men playing a game of poker have been heard echoing through the building and tunnel systems . Many ghost hunts , séances and Ouija sessions have left interesting results , including the recording of electronic voice phenomena , cold spots noted by thermometers , the draining of batteries in touches and cameras , orbs and even misty apparitions . Sounds recorded included sighs , footsteps and a strange dragging noise . The fort was featured in a double episode of the 10th series of " Most Haunted " - a TV show which the UK TV regulator , Ofcom , has ruled is " an entertainment show , not a legitimate investigation into the paranormal " . The ruling also said that viewers of the show were not in full possession of the facts .