Report - - The Citadel’s Southern Defences and Tenaille, Western Heights – Dover 2014 – 2020. | Noteworthy Reports | Page 5 | 28DaysLater.co.uk

Report - The Citadel’s Southern Defences and Tenaille, Western Heights – Dover 2014 – 2020.


rebmeM LD82
Regular User
Few will ever have an appreciation of how stupidly sticky that clay is, how much it coats things, how much it doesn't wash out of clothes and how every little lump you manage to remove is like a mini victory. And how terrifying it is when you almost block the tunnel with backfill and your trapped in this ungodly world for a few minutes with no escape and the water flowing though the clay making a strange trickling sound, yes it was that saturated. I'll never forget the couple of nights I helped out that's for sure!

Calamity Jane

i see beauty in the unloved, places & things
Regular User
Thanks @Calamity Jane i was close to giving up more than once. I don't miss the night of laying in our tight tunnel pulling backfill out. I think your long overdue a trip down this way now? :thumb
I bet you dont miss it, until the next time lol. Im sorry I couldnt dig, cant do shovel work lol. I am overdue a visit. Im just finishing a garden project as I told Sam, and then a meet up would be great. Still need help to get good lite in tunnels. Looking forward to coming down and seeing you & Wevs and maybe LL along the way ;)


Flaxenation of the G!!!
Regular User
Just came across this. That's is an amazing job and total dedication what has laid off. That's proper exploring right here.
Thanks mate I do actually miss all the nights of going for a dig. At the time it was grim but I'd do it all over again for sure


Dragon Temper
28DL Full Member
Crikey. You did extremely well there, well done. Persistence of that calibre is hard to come by these days. Shame that the YouTube and Facebook goonery fucked it up for ages for you. The goons always ruin everything. Well done for getting to those sections!

Gaggle of gays

28DL Full Member
28DL Full Member

The Citadel’s Southern Defences and Tenaille -
Short Casemates and Long Casemates

So what started as something seemingly quite easy myself and @The Wickerman had unknowingly embarked on what would become a 5 year long project of quite honestly the most physically and mentally demanding explore I have ever done. Over the past 5 years of hitting multiple stumbling blocks and completely underestimating how securely HMPS would secure routes out of a prison we finally ticked off another previously unexplored part of Dover. We definitely would not have achieved this on our own and so a selection of dedicated explorers have joined forces with us along the way to complete “THE DIG” - @space invader; @R_yoda ; @m9 ; @Maniac ; @LashedLlama ; @HRed180 ; @Seffy , Riddlers and 3 non members (Welshy, JD & mike)

Firstly let me briefly explain the history and purpose of the Citadel:

The citadel sits on the Western Heights of Dover in Kent, This is a historically significant area being first established in 1779 when temporary fieldworks, comprising small earthworks for infantry and artillery were constructed, capable of temporary resistance against a land assault and for the defence of Dover against naval attack during the American War of Independence.

Plans were soon transformed and a more ambitious scheme for more substantial and permanent fortifications which were designed by the engineer officer Lieutenant Thomas Hyde Page in 1784. A plan from this date shows a large bastioned fortification spanning the western end of the Heights, the earliest representation of the main work which was to become the Citadel.

By 1795 the Citadel had begun to take shape though progress on the construction had been generally slow. There was now barrack accommodation for 60 men.

By 1804 the fear of French invasion had dramatically increased which gave a green light for the further development of the Western heights. Some use was made of the existing earthworks, and progress was rapid, with 480 men employed. By the end of 1805, the earthwork rampart and ditch of the Citadel were established, temporary barracks for a garrison were erected and a well was sunk.

In September 1807 authority was given to revet the west, north and south fronts in brick and to provide the ditches with casemated flanking defences. This decision transformed the Citadel into a permanent fortification.

In 1808 a working plan was provided to show the progress of the earthwork defences of the western and southern fronts, including the tenaille and South Lines as far as the South

Lines Casemates. It seems that their ramparts, ditches and counterscarps were substantially completed, although their brick revetments had hardly been started. However, work on the casemates, which combined artillery defence for the ditches with barracks accommodation, had begun, with those in the South Lines finished and ready ‘for occupation in the spring’, and a pair at the west end of the tenaille also complete (the Short Casemates). Nearby, the Long Casemates were in an advanced state but only two of four sets covering the whole west ditch had been completed.

Work continued at a rapid pace until 1813, the last year of large expenditure on the Citadel, though smaller works continued until funding ceased in 1816. From 1816 through to 1853 the whole of the Western Heights project ceased, with only the Drop Redoubt regarded as complete. The Citadel now sat unarmed and mainly used by locals to graze animals on the grounds though basic maintenance was carried out on the citadel during this time.

By 1853 fear of attack from the western end of the ridge of the heights prompted further investment in the citadel to complete previously unfinished areas, arrangements for further barrack accommodation and the supply of machine guns, rifles and ammunition to arm the fort once again.

The fort continued in operation until the end of the 19th century when it was no longer regarded as a land fortress and by 1907 the Citadel was a large barracks and mobilisation centre and by the 1920’s many of the casemates were no longer used to accommodate troops as accommodation blocks had been built in the western outworks housing 900 troops. Although the Citadel ceased to be an effective land fortress, it received an additional role which was to endure until after the Second World War and by 1900, two batteries had been constructed inside defensible additions to the Citadel.

The Army relinquished control to the Prison Commissioners in 1954.The Citadel was operated by HMPS and converted into a Borstal also operating as a Young Offenders Institution from 1974 until April 2002, when Detention Centre Rules 2001 converted it into an Immigration Removal Centre. The centre provided residential space and shared resources including gym, a library, church, mosques, multi-faith rooms, shops, laundry facilities and a healthcare unit. The site formally closed in November 2015.

The Tenaille and South Ditches

The focus of mine and Wickermans attention began with the southern defences of the Citadel which included the Short and Long Casemates;

The tenaille was a long rectangular ‘island’, between twin ditches, on which were concentrated defences to protect the entire south face of the Citadel. The ditches were badly damaged during construction of South Front Battery in the last years of the 19th century; the outer ditch was removed for three-quarters of the original length and the tenaille cut away.

At the western end of the tenaille, a cross ditch separated part of it to form a demi-bastion, which could be defended independently by gunrooms known as the Short Casemates.

There were three points of access to the tenaille.

The Napoleonic route was from a stair shaft inside the south-west part of the Citadel. The stair descended to an underground gallery which led to a sally-port and also, via a branch, underneath the Long Casemates to emerge inside the Short Casemates of the demi-bastion.

With other routes involving original swing gates leading to the tenaille and the demi bastion from within the citadel these no longer exist though some traces of their locations remain.

Myself and Nick were both interested with exploring the Napoleonic features of the Citadel and its extensive tunnels and defences and had managed to acquire a detailed set of plans.

In 2014 we had started looking at these plans in some detail though with the Citadel heavily secured, regularly patrolled and owned by HMPS we knew there was no chance of even getting down to the moats without triggering the IR cameras and a rapid and heavy response.

We had noticed the Napoleonic tunnel running below the moat and the top of a spiral stair shaft of the sally port which surfaced on the outer bank of the moat and was pretty easy to reach without any bother. After a night of searching around in overgrowth on the bank we located the top of the shaft and the sealed doorway. There was no obvious way in and we were cautious of any noise being heard by a patrol on the other side of the moat. Myself, Wicker_Man and Space_Invader began return trips here. On shitty, stormy nights, slowly trying to work our way into the stairwell, while making as little noise as possible and remaining unseen, took us much longer than expected and quickly became a tedious activity but eventually (with some magic) we had gained access to the stairs. Descending approximately 60ft down the spiral staircase we used the sally port tunnel to pass below the moat of the Citadel. This was pretty insane, we had crossed the moat with no fear of cameras or security for the detention centre. We remained on high alert unsure of whether there would be any official access from the other side and a royal fucking from HMPS.

At the end of the sally port tunnel is a junction, one tunnel leads below the long casemates toward stair leading up to the Short Casemates while the other leads up steps to the rear of Long Casemates. At the end of either direction we were greeted with solid block walls with no way through. I suppose we couldn’t expect any less.

Thus began multiple return trips. On shitty, stormy nights, slowly trying to work our way into the Long Casemates, while making as little noise as possible and remaining undetected, took us much longer than expected and quickly became a tedious activity but eventually (with some magic) we had gained access beyond the block wall.

(Are you starting to see how incredibly repetitive and tedious this explore was becoming yet? But you always feel too close to walk away without just one or two more nights of effort!!)

Beyond the Block wall we were greeted with a 6ft x 3ft room packed to the roof with dense clay and rubble. Well now we know that there’s no official access anywhere and we don’t have to try to do things silently at fear of being caught.

At this point we decided that we should take the other tunnel and go have a look at the Short casemates as this seemed it would be a relatively easy task. At this point my health turned and Space_Invader had decided he didn’t want to make the trip up there anymore and quit.

The Wickerman worked some more magic to get through to short casemates one evening alone and told me to head up there when I was fit enough.

The Short Casemates – 2015

Looking at the litter and graffiti around here we do not believe is had been last accessed since the 1980s. Id taken these photos a year or so after we had started looking into this section of tunnels.

These two casemated barracks, together with an adjacent casemated Cook House, are located in the demi-bastion at the western end of the tenaille.

The barracks also served as gunrooms, positioned to flank the western part of the South Ditch beyond the tenaille.

They were the first casemates to be completed in the Citadel, by December 1808 and could accommodate 21 men in each room.

By 1911 the whole complex was disused,

The casemates were originally approached via an underground gallery, originating inside the main part of the Citadel (see above). This emerged at a doorway in the north wall of the northern casemated barrack, towards its eastern end.

Once we had finished with Short casemates our focus turned back to getting through to the Long Casemates below the Citadel. Myself and The Wickerman began multiple trips up to these tunnels with various tools and equipment and began clearing out all the clay and backfill from the room through to Long Casemates.

We knew some work would be involved as an original open shaft to the surface of about 60ft had been previously filled by HMPS and we would have to get through, under. Over or around this somehow. What we didn’t anticipate was just how backfilled it could be and how solid the clay like mixture had become.

We eventually in 2016 enlisted the help of R-Yoda and Welshy who took a weekly commute down to Dover over the next year to help dig through to the Long casemates.

Despite all our efforts over this period we made very slow progress but continued to excavate the passage and shore up the mass amount of backfill above us. Tons of the stuff ready to drop with one wrong move. We would dig continuously each night for about 10 hours rotating regularly in the dig to keep momentum going.

Many of these nights ended with us asleep on the steps of the tunnels and in the crawl we had dug out. The lack of space, fresh air and pure exhaustion from digging for hours left very little to be enjoyed about the experience.

We continued to work at the dig over about 2 years always underestimating the amount of effort that would be involved to break through. We had eventually excavated through the backfill and across the shaft when we hit a void and much of the clay above gave way to expose a void. COULD THIS FINALLY BE IT??

After squeezing under a metal girder and standing up into the small void I was immediately greeted with a thick wall of yet more compacted clay and backfill.

We were close to giving up at this point but had put too much time and effort in already.

Then fucking youtube/facebook happened and the locals found our entrance posted it all over the internet and 100s of people shot up there to have a look. HMPS got wise to this and filled the top of the spiral stairs with concrete and therefore stopped us getting back down to try Long Casemates.

R_yoda and Welshy gave in at this point and decided to give up on the dig. Myself and The Wickerman thought it was game over and put it on a back burner

Luckily with our access to the tunnel from short casemates remaining then we eventually managed to get up to the short casemates via another route sometime in 2018 about a year after our original access has been sealed. This meant it was game on and myself and nick started regularly heading into the tunnels to dig but knew we would unlikely get far working alone.

From this point Lashed Lama and JD didn’t really miss a dig and we had help from M9, Seffy, Riddlers and Mike on many of the nights we spent digging through the backfill.

In July 2020 cries of joy were heard from the void as Lashed Lama finally broke through with the shovel and exposed the Long casemates for the first time since filled in the mid 1960s. After a long night of digging Sam, Law, Seffy, mike and myself were finally in the Long Casemates.

Long Casemates – 2020

The area of these Napoleonic casemated barracks, in the south-western part of the

Citadel, had been filled with debris and the entrances blocked in 1967, leaving only the southern elevation of the southern pair visible.

The interiors are not accessible since they had been sealed by HMPS

The group consists of two pairs of two-storeyed casemates, situated to the north and south

of what was originally a deeply sunken area serving as a light well.

The southern pair were designed to defend the ditch at the south-west end of the tenaille, and were described as ‘not finished’ in 1808.

The northern pair appear to be entirely buried behind backfill while the southern pair which we had gained access had been completely filled at ground level leaving no visible trace of the lower floor expect some holes in the windows which have been bricked.

The Dig involved a total of 5 years work, excavating rubble, and backfill clay and soil 1 x 25L tub at a time via a human chain through the crawl. In total we have dug a distance of about 40ft and to a height of about 10ft at a 45 degree slope.

That's it for now. Hope you enjoyed the report as much as we enjoyed all the nights put into making it happen digging into the relatively unknown. For me this is what exploring is all about. :thumb
Great report im still yet to do the long casemates not found the way into the dry mote yet lol