Report - - Sapperton Tunnel March 2015 | Underground Sites | 28DaysLater.co.uk

Report - Sapperton Tunnel March 2015


28DL Full Member
28DL Full Member
Full kudos to Bertie BBrains for this one, the idea and research was all his. Being invited along without having to spend hours researching etc was a welcome change and, as always a good time and adventure was had by all. Joined on this trip by Clemo, a non-member and free-loader extraordinaire, he fitted straight in...
Sapperton is a stunning little hamlet with expected expensive properties and suitably nosey retired folk. We got a few curious looks by the yokels by changing into waders and trotting down the hill carrying an inflatable dinghy over our heads but needs must.


For many years the worlds longest tunnel, Sapperton is almost 2.2 miles long. Built over six years, work started in 1783 by setting out the tunnel route. 26 vertical shafts were then dug out along the route (some were about 200 ft deep) before small tunnels were dug joining the shafts. Once they were all joined and alignment checked the tunnel was excavated to the full size and lined with stone or brick as needed.

The tunnel was dug by navies who were housed at The Barracks, a terrace of cottages about quarter of a mile away. Gunpowder was used to blow the solid rock parts, the rest was hand dug using simple tools and wheelbarrows. The spoil was winched up the shafts by man or horse and tipped- Beech trees now grow on these raised spoil heaps.

The tunnel always had problems right from the start-two natural springs had to be redirected and problems with the 'fuller earth' absorbing water...little wonder really, its the same stuff cat litter is made from. This earth kept pushing up effectively making the tunnel shallower and stopping boats passing. To stop this the brick invert was replaced by 20-30cm wide wooden struts which should also prevent the walls from pushing inwards. It hasn't.
We saw a couple of these timber struts now broken and rotting away gracefully.
There was never a towpath on this canal, progress was made by 'legging' - lying on your back and walking along, feet against the tunnel roof.


Explored in two visits, firstly with Bertie checking out the Daneway end, simply by wading out and climbing over rock falls. When the path was completely blocked we turned back and visited the Coates portal a few days later on our own....

Daneway portal, in a Gothic style was restored by the Canal Trust in 1977

A few feet in is this charming brick pattern

And some pretty amazing calcite build ups

Note the chain maker- a chain is a measurement of 66 ft

And some pretty nasty wall bulges

First fall in

At the top of the fall in, it all changed. The air was different, the water was about 6ft deep and amazing clear and cold - especially if you're not wearing waders, hey Bertie? Check out the deformed brickwork struggling to hold the weight.

This revealed a fall-in so big it completely blocked the tunnel so we backtracked to the car and hatched a new plan.
One of the huge sink holes, dropping a stone in revealed a 3-4 second wait before the splash below..

Driving to the other end of the tunnel, Coates portal, revealed a set of gates about 20ft in. One of us had to check access so the ever suffering Bertie was volunteered. In you go fella, wont be that cold.

After pulling the shaking Bertie out and forcing a drink down him at the local pub we all said our goodbyes. Bertron re-visited on his own whilst we decided to do it another way.
Which is when it degenerated- in a farce worthy of a 'Carry On' film we ignored the prepared method statements, meticulous planning and risk assessments (having ensured our safety helmets, life jackets and mobiles were safely secured in the car boot quarter of a mile away,) we then punctured our brand new kayak on the entrance gate and had to inflate HMS Saveloy continuously as we pressed on in the best British tradition.

The water was so shallow in places we had to get out, lifting it over fall ins and trying not to get the camera kit wet. A gentle 30 minute or so paddle brought us to the first fall in and its a big one. Entire sections of brick have cracked and moved. Other sections have started to bulge but this end is in way better condition then the Daneway end. We stop, repatch the saveloy, explore by foot (or waders to be accurate,) then have lunch and soak in the atmosphere and sheer work that must have gone into making this structure. Considering this place hasnt been maintained for a century its incredible.

The Coates portal, neo-classical style, also restored in the 1970's

Some repaired sections, graffiti and warnings




Earthenware pipes, something to do with the re-directed springs?

Another chain maker, change of bricks and black line that denotes a wooden strut added later to combat movement.

The first fall-in revealed massive bulges and deeper water

The second fall-in was enormous, the air changed, the water had skum on it with huge cracks everywhere you looked. We stopped and had lunch.

After this fall-in it was game over...definite air change and at times like this you find out what you are made of- in our case it was jelly, so we left.

We saw a couple of things we,d missed earlier on the way in- looking up at the only vertical shaft not bricked up

What the best dressed 'canal trippers' wore in 1911

And today...

Some random loveliness to end on..




As always,hope you enjoyed and thanks for looking.

Bertie Bollockbrains

There is no pain
Regular User
On the way to the falls at least, you actually saw more than I did, and better photos - but then I didn't have the luxury of a boat and couldn't really take photos in-water. Looks as if I got a little bit further than you two. Thinking you got to about chain 78, whereas me 82. The half way point is marked on the wall, and I must had been not far short of it. The 2008 Canal Trust survey reached to 102. Theoretically it should be possible to get to the complete Daneway Portal blockage from the other side at chain 158ish. Maybe a target for the summer. Did you notice since the first visit, how the water levels are rapidly going down? I think this could be very shallow and easy wade in the summer.


Fear is the little death.
Regular User
Did you notice since the first visit, how the water levels are rapidly going down? I think this could be very shallow and easy wade in the summer.
When we used to do the walk to the tunnel as kids (circa 1984ish) the Daneway side was completely dry and we were able to walk up the tunnel a good hundred feet or so to the metal doors. If we get a good summer might not even need wellies.


28DL Full Member
28DL Full Member
Thanks for all the replies, appreciate it and the 'thumbs' or 'trophies' whatever they are now called. Its a dangerous place, no doubt...agree in the height of summer you could wade the entire length, but after the big fall-ins the depth really changes. Also the gases will still be there all year round.

Chelt original

28DL Full Member
28DL Full Member
good stuff mate, i couldnt do that, as many miles of river ive walked following my hobby of old bottles i couldnt bring my self to do that. water not far from my nads or silt above my ankles and my heart does pump! how the fk he swam ill never know! off subject but apparently the tunnel house use to be a good place for a mashup in the 90s.


28DL Full Member
28DL Full Member
Cheers Chelt,speak soon,was more of a walk with only certain parts deep enough to swim or need boat at the moment. It's bloody massive,would have taken some building!