There have been fortifications at Coalhouse Point to guard the Thames approaches to London since the 16th century, though the present day Coalhouse Fort was built in the 1860s as a byproduct of an arms race between Britain and Napoleon III’s France. Like many forts of the time, during the decade or so it was being built, advances in weapons would render it virtually obsolete. Even so, it is still considered to be one of the finest examples of an armoured casemate fort in England.
Its design incorporates twelve casemates facing the river to the south and east, and these are protected by massive granite walls and cast iron surrounded gun ports which would protect gunners from stone splinters caused by enemy fire. Within the casemates, manual ammunition lifts were provided to allow shells to be brought up to the guns from the magazines below.
Later refinements in the 1880s to meet new threats led to concrete walls being built to separate the casements from one another, and at the same time the shell lifts were extended up to serve additional rooftop guns. The additional load of both required significant structural alterations.
The magazines are beneath the casemates and alternate between cartridge and shell stores, accessed by a ring passage on the outer osde. Meanwhile at the rear of the stores there is an inner lighting passage, providing illumination by oil lamps while being physically separated from the stores to reduce the risk of explosions.
It was altered in the 20th century when, first, 12-pdr quick-firing breech loading guns were added to its arsenal when it because a First World War Examination Battery, and then in the Second World War anti-aircraft guns were brought in. It became redundant in 1949.
For opening times, plans, photographs, etc. refer to Coalhouse Fort.