Report - - Fort Clarence East Castemates, August 2020 | Underground Sites | 28DaysLater.co.uk

Report - Fort Clarence East Castemates, August 2020


Wasteland Wanderer
28DL Full Member

Really excellent place, incredibly well tucked away and as a result I didn't see a single piece of modern rubbish inside, not even a monster munch packet or a stella can. Nice to see somewhere a bit older than the usual Victorian Palmerston Forts after having seen plenty of those.

Explored with @LashedLlama - we set out after dark with the best precautions and had a clear action plan. The access was straightforward, but with a degree of ninja involved and prior knowledge being a must. At least that's without complications, but typically there very much was, and it was very difficult to get around without challenging directly. After being about to give up, we had one final idea - "If we pull this off, that would be ridiculous" is what we said. And without giving too much away, we bloody well did. We had to take an incredibly overt approach involving questionable social skills, and as much as things became horrifically awkward, as the saying goes 'any method that works is legit' (alright I made that up). But it really was worth it, and the contrast between the location beneath and the outside world was really quite impressive - classic underworld vibes. So here you go:


Most of the history online focuses on the fort itself or its other associated structures. Even the English Heritage report at the bottom of this description admits 'The [East Castemates] are intact and were not damaged by the redevelopment of the site. However, only a brief inspection was made during the course of the present survey, insufficient for a considered description and interpretation'.

Fort Clarence was built between 1808 and 1812 to defend presumably against the French in light of the Napoleonic Wars. Its architecture showcases a nice mixture of both the contemporary 'parabolic' archways which I have not seen before, and the more familiar Victorian-style arches (presumably original pre-Victorian however). The fort consisted of a long dry ditch running from Maidstone Road east to the River Medway west, with guardhouses at each end and a big old gun tower keep in the middle; visible today as private homes after a refurb. A drawbridge demolished in the 1930s crossed the ditch, and the ditch contains two sets of underground castemates both east and west.

The East Castemates appear quite similar to the western ones judging by photos in the heritage report albeit with some slight differences presumably to work round the shape of the moat (in the case of the eastern ones it lies at a right angled turn). All contemporary external openings of the castemates are bricked up, although originally one way would have faced east along the ditch to Maidstone Road, and the other south. These defensive positions were linked by two casemated(?) ante rooms, one of which loopholed for musket fire and both with steps leading to the surface still visible. If these are the bits I think they are then the loopholed position facing the steps to the surface could be described as a sally port bearing two tunnels running parralel; one for the entrant, one for the defendant, behind grated viewing holes. From here, this entrance could be controlled by the defender using two 'remote controlled' surviving metal gates. The two central casemates consisted of two large chambers with vaulted ceilings and various surrounding arches. They would have been two-storey, but today the second floor is visible as a floor-covering of mouldy rotten wood. From these the various tunnels offshoot. Each floor had a fireplace. This is all the information I can find - any more info or clarification, please do help.

Full heritage report can be found here:


The EH plan included below doesn't quite look how I remember it to me. The plan seems to show three pairs of adjoined large rooms, but what I saw felt more like two large rooms with various tunnel offshoots?


















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Flaxenation of the G!!!
Regular User
Those photos are bang on the money. Top work lads. Lovely place this.