Victorian Cliff Tunnel, Portland, Dorset

I thought I knew Portland. I thought I knew it like the back of my hand. Discovering this incredible tunnel back in 2014 was the equivalent of finding out that your wife of 32 years is actually a man, you’re adopted & Father Christmas isn’t real all in one day! I mean, if this tunnel could remain secret for so long, what else does Portland hide?

Open manhole showing the entrance to the Victorian cliff tunnel
The unassuming manhole covering one of Portland’s best kept secrets.

So many myths & legends are banded around Portland’s modern-day folklore. Most tell of expansive tunnel systems, “nuclear” bunkers, secret passageways & the rumour that just won’t go away, the infamous submarine pen! And while there are many underground spaces on the island, none are secret enough that you couldn’t find all about them with a little research and a couple of spare hours on a Sunday afternoon. But this tunnel is pure unicorn, Atlantis, Nazi gold, the Holy Grail! Okay… perhaps I’m getting a little over-excited, but it’s not every day you uncover something that you had no idea even existed. Something you have walked over countless numbers of times and were none the wiser.

The steep, unstable cliffs of The Isle of Portland, Dorset.
The steep, unstable cliffs of The Isle of Portland, Dorset.

Stepping in to the unknown, we had to have our wits about us. Hard hats, safety gear & gas meter in hand, essential items for underground exploring.

The tunnel, situated on one of Portland’s highest points, is carved straight through the cliff at an exceptional gradient. It has to be 45 degrees, maybe more. Climbing the full distance up the huge steps, your legs burn as you reach the top, each step harder & harder to take. It’s unclear what the tunnel was originally used for, perhaps just a bit of a Victorian folly? An interesting, different route to the shore? However alongside the steps, a waste water pipe is still hard at work. It’s hard to believe that this spectacular tunnel was simply a glorified waste pipe!? Although it seems that’s exactly what it is.

At the foot of the tunnel, you’re surrounded by concrete and large Portland Stone block-work. The tunnel itself stretching out in front, high & distant with no end in sight. It’s here where the tunnel feels somewhat new and safe, as you walk up the steps the ceiling is concrete lined and the block-work continues, and then all of a sudden, it stops and a massive fault line in the cliff scars across the roof and the tunnel turns to bare rock. It continues this way until the very top where the concrete reappears and surrounds the surface manhole. It’s funny standing here, listening to people walk above, and cars drive by clueless that someone is beneath them! There’s a few modern day fixtures and fittings, a handrail, a safety barrier at the top in case anyone entering slips, and data cables running the entire length which suggest the tunnel still has its uses in the 21st century.

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Important, noteworthy & interesting comments are highlighted below

  1. Very interesting. I’ve got a few theories why it’s so steep, but would have to see the place for myself, maybe it will be unsealed again in the future for me to have a look

    Some explorers will show the entrances to compound the entrance being sealed up so they can be the last to do that explore before getting sealed again. This is so they get more hits on there site or channel, this could be why the the last person showed the entrance and how to access this interesting Portland cliff tunnel.

  2. Brandon says:

    Any idea if this is still accessible? Trying to find places local to explore nowadays is super dead, getting lost in the quarries whilst its dark and foggy is about as fun as it gets on the island lol.


    1. Danny says:

      Sadly, some idiot decided to post entry details all over social media and got the tunnel locked down.

  3. Ian Wolff says:

    Hi there, I have been thinking overnight and am now not sure if we actually climbed down into the tunnel (it was 45 years ago!). We definitely dropped some stones through the hole we made and heard them bouncing down the steps and pipe. Can I send you a new post after I finish work this evening?

    I’ve lost contact with most of the other people who were there but have one contact who may have a recollection of the cave.


    1. The Urban Explorer says:

      I think you’re probably right, Ian. I’ve spoken to some cavers and they say there’s a route right across this tunnel.

      1. david hayward says:

        I think so. This is interesting

      2. Philip Keightley says:

        Hello Urban Explorer
        I’m due to visit Portland next month and would like to visit, I have been to rotor station etc, but never knew of this. Any chance you could send me the location. Many thanks Phil

    2. Adrian Dewar says:

      Hi Ian, I worked in tunnel including relining the bottom shaft back in the mid 90s

  4. Ian Wolff says:

    Back in the 70’s a group of us were exploring the rift caves on Portland. Exploring one, we were surprised to find some brickwork partly blocking it. We removed some of the bricks and were able to drop into the space below. Although many years ago, my recollection of what we found must have been this tunnel. After a quick explore we clambered back out and replaced the bricks. It was probably at the fault line you mention.

  5. tony white says:

    Hi, was there a tunnel which the prison used to use for convicts via the old railway. Also linked to an underground chamber under the YOI (sealed off 20 odd years ago)

  6. rick davies says:

    Am I close by saying it’s close to the incline road?

  7. Jon Illaley says:

    This is accessed from the YOI car park. There is a locked steel door in the car park with steps descending beneath.

  8. cmunts says:

    Hi, Urban Explorer I have a feeling that the tunnel might go from the high angle batteries down to the east weare batteries. Maybe used for when they needed ammo taken off boats taken through the east weare batteries up through the tunnel to the high angled batteries.

    1. The Urban Explorer says:

      Nice idea, and makes sense! Although I wouldn’t have liked to haul shells up those steps without a cart and/or pulley system! It’s definitely nothing to do with the batteries.

  9. Ross says:

    Reminds me a bit of the underground hospital entered via a now SEALED entrance near the prison car park. However it was not hidden by a manhole cover? Portland is scarred with history of all sorts! There even used to be a downwards set of steps in the hospital grounds that was sealed many years ago. Good luck exploring people there is much more to find!

    1. The Urban Explorer says:

      The set of stairs you mention were on top of the grass hill, right? They went in to the underground hospital. I’m not sure what you’re referring to in the prison car park? There might have been a citadel hospital up at The Verne as part of the many underground spaces they occupied, but the underground hospital is located in the modern hospital grounds.

      1. Ken chant says:

        Hi Urban Explorer, I myself live on the island as well and was wondering where this is please can you email me and if you’re ever out and about would love to go exploring with you. I’m a history nut and love all this sort of thing please help me.

        1. Charlie Thompson says:

          Hi do you know where this place is? I’m an explorer with a YouTube channel and it’s very interesting about the history can you please email me at as I would like to check out the history kind regards CT

      2. Aaronleeroberts says:

        Hi, I have my own YouTube channel and would like to share this experience with my viewers of course we will not record until we are in the tunnel were abouts is this entrance or do you have an exact location of this man hole cover

        1. Daniel Drinkwater says:

          My and some friends are wanting to go and we have no idea how to get in


  10. Avnish says:

    Hi there, me and my friends have been looking for the exact location for days, is it possible to message me with the location of its whereabouts? Great find by the way.

  11. Craig W says:

    What a great find. Myself and a couple of friends have explored many of Portland’s hidden underground world. I would love to know where we can find this entrance so if there’s any chance you can share the location with me via email please do and if not then I completely understand. I’m sure we’ll come across it at some point in the future. Great pictures and thanks for sharing.

    1. Daniel Drinkwater says:

      If anyone knows any of these locations including the underground hospital get in touch me and some friends are wanting to do our first explore


      1. Philip Keightley says:


        Did you find the tunnel location, mate? Any chance you can email it to me please.

  12. Craig says:

    I’m a young explorer myself and I want to find this as I live on the island

  13. Sean says:

    Thanks for sharing your adventures, I have a great love for the island and your adventures are really interesting to follow. Keep up the good work.

  14. Karly says:

    I love the picture and I wish they would do tours of them

  15. Jwalker says:

    Awesome pics and more evidence of Portland’s subterranean secrets. Would love to have a look in here. Any hints on location. Pretty please =3 or you could mail me privately.

  16. Jax says:

    Great photo’s. Reminds me of something out of Lost! I would love to find this place ;-)

  17. Natalie says:

    Nice one.
    I’m pretty certain I know where this is – or at least the bottom of the tunnel?

  18. Tom says:

    I think I’ve found the location, however there are some gypsies living there and it’s a bit sketchy!

    1. The Urban Explorer says:

      I know where you’re referring to, and no, it’s not there.

  19. David Crooks says:

    Great photos mate and really interesting feed.

  20. John says:

    Hi. Great find. I was told about a sallyport from prison governors house to dockyard could this be it? Not sure where your find is so could be miles off but pictures just reminded me of it. Great report.

    1. The Urban Explorer says:

      John, I know what you’re talking about but no, this isn’t connected with it.

  21. Sara Harpley says:

    You sound just a teeny weeny little bit excited about this one :-) Great find and really interesting.. Thank you!

  22. Danny Kelly says:

    What an incredible find. Congratulations, and as you say, what other interesting places has Portland yet to yield?

    1. Marc says:

      The underground city below the Southwell business park for one!

      1. Steve says:

        Have you got any pictures of the underground city?

      2. The Urban Explorer says:

        Interesting you say that, Marc. I’ve heard this rumour a few times and once thought I found an entrance which is sadly long gone now.

        1. Marc day says:

          I met a guy once who swears he’s been down there, signed an official secrets act and everything lol, and would not reveal its whereabouts other than it’s real and exists.
          I was always led to believe it could be accessed via an elevator inside the business park but it sounded a bit James Bond lol

  23. Steve says:

    Wow. What a find. I want to find this now. Great pictures as always.

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