Naval Fuel Bunker, Portsdown Hill, Hampshire

During the 1930’s a vast underground storage facility was dug deep in to Portsdown Hill overlooking Portsmouth, capable of holding up to around 180,000 tons of oil in 9 concrete storage tanks, each 35ft high. During a few visits to the site, we managed to see the entire place.

Portsdown Hill fuel bunker
Portsdown Hill from the M275, with the T45 test rig on the horizon and Paulsgrove chalk pit underneath

Portsmouth’s naval history is a long & proud one which the residents of the city are constantly reminded of living in the shadow of Portsdown Hill. Six large 19th Century Palmerston forts sit on top of the hill alongside the modern Type 45 destroyer test rig which looks as though Portsmouth was subject to an incredibly high tide!

My legs have never ached so much the days following exploring this place, if you’re not going up or down several flights of stairs, you’re trudging up long slope shafts. Perhaps that says more about my physical fitness? There are four entrances to the fuel bunkers, officially labelled North Compound, Top Entrance, Main Access Tunnel & Access Tunnel. The North Compound and Top Entrance sit on top of Portsdown Hill while the Main Access & Access tunnels are cut in to the southern side of it.

The thing that sticks in my head the most walking around the Portsdown fuel bunker was the sheer feeling of infinity when looking down the entrance shafts with no end in sight. Endless walking and feeling like you’re getting nowhere.

Decommissioned in the 1990’s, Portsdown fuel bunker is still in great condition, although the pump room (the deepest part of the bunker) is quickly becoming an oil-filled swimming pool. Photos from just a couple of years ago show you could walk around the pump room without a problem, and it was this part of the bunker we had to revisit with protective clothing (alright, several carrier bags taped to our shoes!) in order to see it. Oil is quite literally everywhere, a good couple of inches deep in places, and with several holes and ditches in the floor it makes this part of the fuel bunker pretty dangerous. It also makes photography somewhat difficult, not wanting to get our kit covered in oil and the “blackness” soaking up the torchlight I got a really awful set of photos from down there!

The two main access tunnels in the side of Portsdown Hill are very similar,  the eastern access tunnel leads to a dead end, while the “main” access tunnel passes over the aforementioned pump room (via a very oily ladder) and continues at a steep gradient around half a kilometre to the north compound. Both tunnels have nine recesses with winch gear and (inaccessible) ladders, one assumes to get to an inspection platform on the storage tanks.

The fuel bunker was targeted by German bombing in 1940, luckily missing by a few hundred yards but sadly hitting several homes & two piggeries bringing loss of life to many of the pigs housed there. Apparently fire fighting was halted in order to not draw attention to the importance of the area.

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Important, noteworthy & interesting comments are highlighted below

  1. Ollie says:

    Went here recently, can confirm that the two southern entrances are still tightly secured with huge metal doors with metal wire crates filled with small rocks to block access to the doors.

    The third access around 280metres north of the portals looked to still be blocked but didn’t actually try it. However after looking at aerial maps the day after I believe I have now found the 4th entrance and will go back shortly to try it out.

    Will update in a reply.

    1. Sam says:

      Would love to join!

    2. Alexander Savidge-Conway says:

      Where? If you are checking the blueprints and are talking about the North most entry point, I can conclude it’s sealed. And getting there is full of thorns.

    3. Alex says:

      Hi did you manage to find an entrance?

    4. Toby says:

      How did this go? Did you return and find the possible 4th entrance.


      1. Ollie says:

        I’ve found it on Google maps yes but I’ve been told by multiple people that it’s closed up now.


        1. T says:

          Went and searched for the entrances last night.

          Northern compound is bricked off. Valve compound entrance is demolished and filled in with concrete. Both southern compounds are completely blocked off with wire crates of bricks and on top of that the metal doors have been welded.

          Unless there’s another secret entrance there’s no way in…

          1. Ted says:

            Have found all 4 entrances and will be going to check them out soon. Will update after I have been

    5. Aron says:

      Hey Ollie,
      how did it go? Was thinking about heading there but not sure if I can access it.
      If not, any recommendations?

    6. Tj says:

      Did you find a way in?

    7. Em says:

      My dad worked here for years and walked the line from Hilsea Road to Gosport, I remember staying with him the night there, there is a massive room with what looks like 30ft steps in it crazy place.

  2. Baz says:

    Paid a visit last night with the missus. Both South entrances are still very much sealed with the doors welded closed and RSJ’s welded to the doors. The North entrance that people have mentioned is no longer there. This has been demolished and back filled.

    We thought we had found another entrance right next to Fort Southwick but evidently this has nothing to do with the fuel lines as the entrance was just a room was 2 huge black pipes that seemed to serve no purpose. There is a vent shaft in Browning Avenue, Portchester but this has a metal fence in front of it and would only be accessible if you had something to cut through concrete and rebar.

    1. The Urban Explorer says:

      There’s 4 entrances in total, Baz. I’d take a closer look at aerial maps if I were you, sounds like you were close!

      1. Baz says:

        Yeah, after I posted this I realised my error and think I have found it. Going to check it out at a later late

        1. The Urban Explorer says:

          Great! Keep me posted.

          1. Baz says:

            Took a look up there this evening. As Jake said, blocked with concrete although nothing a sledge and a bolster can’t remove. It looks stronger than it is.

            1. Matt says:

              Went down there a week ago during the day to have a look around and see if there was a way in, both South entrances sealed but still cool how the noise from the M27 started to disappear as you walk up to the doors. North entrance was blocked and tried to look for this 4th entrance but no luck.

              Been looking on aerials as I’m planning another trip and seen 3 places on the surface Valve compound and 2 others for possibly the 4th entrance wondering if I’m close or can get a hint.

     if anyone wants to point me in the right direction.


              1. Draven says:

                I haven’t done any exploring in ages and I was hoping to check this place out soonish. Does anyone have a location of an entrance? Even if it’s a difficult one. Please email me at. if you can help please!

        2. Jake says:

          I found the 4th entrance but it’s been filled with a massive block of concrete

      2. Oneway says:

        Shame to see it in the state it’s in we went in a few years ago now when it was in really good state I still have photos, I live in the area so always been interesting to me I remember going up the big ramp where the shed was and seeing urbex spray painted near the upper level bunker

        1. The Urban Explorer says:

          Ugh! I really don’t understand the need for people to deface these places?! Whoever graff’d “Urbex” doesn’t represent this hobby, they’re an idiot.

          1. Oneway says:

            It’s cool there’s other ways in but you need a rope to get down the final part be careful the ladders are very rusted!

        2. Ged HallM says:

          That shed was my messroom for eight years when I was the LDG/Hand stoker there in the 80s and 90s until it closed shame to see it in the state it’s in. The best job I had.

      3. Alex Savidge_Conway says:

        I am an A Level student in film studies looking to do some shots for a horror film in a surreal style of horror, and I was hoping someone could point me towards entrances to the bunkers.

        1. Oneway says:

          Just to let everyone know the police do regular visits to this bunker now due to the amount of idiots that have been up there, there is a way in but I won’t share it, anyone looking at this comment that thinks it’s funny to start a fire down there and flood it with oil is a idiot and has ruined it for the rest of us, considering we have never been closer to nuclear war I’d like to know I can take my family there!

          1. VT says:

            There is still a way in? I thought all entrances were blocked up
            I cannot see any way in, and I have looked carefully at the overlay of the fuel bunker several times.

          2. Adam says:

            Is there really a way in? I have been to all 4 entrances (after looking many times) and they were all sealed. I live local and would really like to see it. Is there any chance you could help? Even a clue?

    2. Adam says:

      Did you find it? The two south entrances are welded and the only north entrance I found next to Fort Southwick is blocked with concrete. Is there any other way? A

    3. Cyrielle says:

      Is there people living in there? Like a mole people community?

  3. Harry says:

    Where about is it and how do you get in

  4. Tom says:

    Are there any entrances still open?

    1. John says:

      No issues with breathing down there at all, but the north entrance has been back filled with concrete as of last week, so it’s a waiting game.

      1. Gabe says:

        Is there anyone that can give me a postcode for this?

        1. Daniel says:

          Did you find it?

    2. Jake says:

      I can confirm the entrance is blocked with a full wall of concrete. Pretty tough stuff, would take a bit of work to get through. No doubt someone will and will be available to explore again. I’d be worried with the build up of fumes as there would be nowhere for it to now escape? Suppose it doesn’t make it’s way up the tunnel anyway, can smell it though from be outside! Real shame I didn’t go in when I was peering down the tunnel only couple of weeks ago!

      1. The Urban Explorer says:

        There is more than one entrance/exit to the fuel bunker.

        1. Pete says:

          Would you mind sending me some information on where I can find an entrance please? I’ve been walking around trying to find one but just can’t seem to! Thanks,

          1. natalie says:


            Did you get sent any information on entrances to the bunker? I’d like to go this weekend. Or have you got any others in Dorset or Hampshire worth visiting?

            Thanks, Natalie


        2. Mike says:

          Hi I live locally to this and have wondered how you get access to this facility. If anyone is going, drop me a line as I would be up for a look round.

          1. Hollie says:

            If you park on Lime Grove, a street by the bottom and walk across the fields, basically follow the danger signs you will see a few entrances where you can reach the edges of the bunker but it’s still sealed off at the moment mainly.

          2. Ben says:

            Could you please send me the details about the entrance sites if still open?

        3. Bayley says:

          Hi please may you direct me in how to enter this bunker? I would be very grateful.

        4. Shane says:

          Is there still a way in that’s all I need to know

          1. The Urban Explorer says:

            It’s impossible to say, Shane. Access to abandoned locations changes daily! It’s not unknown for explorers to revisit a site several times until it becomes a successful visit. Good luck!

          2. Mary says:

            Can you please email, please of the location.

            1. Mary Everley says:

              Still awaiting a reply please.

              1. Lewis says:

                Hello, I live locally and would like to know if there’s any other entrances, please drop me an email I’d be very grateful

                1. Johnny says:

                  Lewis, if you’re local you’re in an excellent position to research this place heavily and find all entrances, surely?

                  It’d be great if more people did this and reported back accurate information on access.

            1. Nigel Evans says:

              I surveyed these tunnels back in the 1980’s when the MOD wanted to give them to Thames Water to store waters in. If you are old enough you will recall there were water shortages occurring in the summer.

              There are 9 tanks as I recall 7 are 700 feet long with 2 shorter ones. tunnels are possibly 500ft long. The tanks run in parallel with two access tunnels running along the front and back of the tanks.

              I recall the tanks having several inches of oil sludge, which would be dangerous as they will release dangerous fumes, (I guess this blog led to somebody being told the get the entrances blocked off). To ensure nobody is found dead in them. The sludge meant that they were unsuitable for alternative use.

              The engine powered the ventilation plant.

              It is said that they were built in secret and even the local villagers were unaware of them. I may still have some plans from the report I prepared back then.

        5. Nicky says:

          Hi can you tell me where the other entrance is please

        6. Derri says:

          Any chance you could email me about this place regarding entrances

          1. The Urban Explorer says:

            Feel free to contact me if you have trouble.

            1. Sophy Hoare says:

              How would I go about getting in here please?

              1. The Urban Explorer says:

                You’d go and have a look to see if there’s a way in. Sorry to be blunt but that’s all there is to it!

            2. Dillan Hudson says:

              I’ve been wondering are there any entrances open to access the tunnels? Thanks

        7. Matthew HUDSON says:

          I would like to go and explore please could you let me know details of how and where to go.

        8. Jake says:

          Really want to visit this place could anyone help me with finding an entrance please 🙏 happy exploring everyone

          1. The Urban Explorer says:

            Check your email, Jake.

      2. Adam says:

        Could you send me the details of this entrance please

        1. Jake Davies says:

          I believed this was still blocked, I was a day late to go inside as they’d just started filling it in. If you found a way, or anyone has, please let me know! Thank You!

      3. Lewis says:

        Is there any possibility the wall could be climbed or is it completely sealed off. P.s I’m a very good climber

        1. Jake says:

          It’s completely sealed up. Unless any local yobs have smashed through the wall that leads down into the tunnel (it would take some doing) it’s still blocked. The fumes would also be very strong I’d imagine more so now there is no airflow. Not going to have much luck finding a PPF3 mask right now! Good luck though – If you do head up that way, let us know if it’s unblocked!

          1. Nigel Evans says:

            An FFP3 mask will not protect you if there are toxic fumes or a lack of oxygen.
            Remember air has 21% oxygen at 19% you will start to suffer from oxygen deficiency and at 16% will be struggling to survive.

      4. Ross Hall says:

        There’s now a way in was there 13/09/2020

        1. Jacob Harper says:

          Which entrance did you use?

        2. Paul Reeves says:

          Spill the beans lol

          1. georgia eve says:

            Just found a possible way in, requires some climbing though!

          2. Ross Hall says:

            Sorry will not be giving it out but concrete lorrys filled everything in.

    3. Tom says:

      Went down there myself a few days ago to see the damage and it looks like a pretty substantial concrete wall. However, [** removed **] looks easier to gain access through.

    4. Adam says:

      Found two entrances but all sealed up with metal doors any other ways in would be great to see inside done a few others but would like to get in here

    5. steve says:

      I’m local and have been in there with my boy.

      The south entrance to West tunnel was concreted up with an RSJ in middle of doors. Since then the fence holes have been addressed. Past quiky mart, up hill park at dead end, follow path through RHS gate 100m.

      1. Troy says:

        Is this an entrance I take it?

  5. Mark says:

    Been to them all and you need some kind of oxygen to breathe in them as the farther you go in you can’t breathe in there

    1. The Urban Explorer says:

      Interesting. Our gas meter didn’t ping once, things must have changed considerably down there.

      1. Will Woodhouse says:

        Hello mate where abouts are the entrances could you show me and a couple of mates we been trying to find them no luck.

        1. Dan says:

          Mate, I live in Nottingham and I’ve never even been to Portsmouth. Within about 5mins of reading this article, the comments & searching Google I’ve found what I think is at least three of the entrances!

    2. Rick Terry says:

      You been in there where you find way in I live this type of stuff

  6. Gaz McCulloch says:

    Hi, recently moved to port Solent and have started walking the hill. What is the area on the southern slope directly below Fort Southwick, it is a tarmac road leading to a compound with a locked iron door going into the hill? I find it very interesting up there.
    Many thanks
    Gaz M

    1. The Urban Explorer says:

      Hi Gaz,

      You have found one of the entrance tunnels to the fuel bunker. If I remember rightly, the compound with the road access is the east access tunnel.

      Portsdown Hill, Naval Fuel Bunker map

      1. Gaz McCulloch says:

        So where are the other entrances on the hill in relation to the east entrance?

        1. The Urban Explorer says:

          If you rotate that map 90º and just overlay it, it’ll all become very clear.

          1. Gaz McCulloch says:

            Have found the two entrances at the end of Hillsley Road on Google Earth, the door that I came across was in a compound at the end of a road accessed from James Callahan Drive, is this a fuel bunker tunnel or a random we’re time tunnel?

      2. Johnnny says:

        Where did you get that ‘map’? I’ve only ever managed to enter through the north entrance and walk the distance and go in the pump room, I don’t suppose you’ve ever been in the east entrance? Be interested to hear! Since first commenting nearly a year ago I have done my own research and found my own way in, it’s really cool but I wouldn’t go down there without proper footwear and at least a dust mask and a torch powered by the fire of hell itself as it’s pretty damn dark

        1. The Urban Explorer says:


          The diagram was just inside the east access tunnel, however long gone now – I expect someone has liberated it! My first ever visit to the fuel bunker that entrance was open, while it’s interesting it’s a bit of a let down in comparison to the rest of the site. The photo with “7” painted on the wall is from the east tunnel, from memory the entire tunnel is like this, straight, long & with the occasional alcove for the fuel cells.

          1. Shane says:

            Is there still an entrance in by the pump room?

            1. The Urban Explorer says:

              No idea Shane, it’s been years since I visited the site I’m afraid.

      3. Gary McCulloch says:

        Been up today, 1 entrance is open. Now located all 4. The ww2 bunker and radio station

  7. Johnny says:

    Went today, it is still accessible via the other entrance and seems like the flooding may have subsided? Didn’t go all the way though so who knows

    1. Joshua Lothian says:

      Where is this entrance. I’ve looked online and everyone is saying it’s all sealed up?

    2. Zach says:

      Hi, i live locally and wondered how to get access and where? Wondered for a long time how to get in there

    3. Mark Harrison says:

      Any update on this, would very much like to get in to have a look about. Checked the main tunnels but couldn’t get in. Any tips would be appreciated…

      1. Paul says:

        Fencing has been repaired as of 30th November

    4. Gaz McCulloch says:

      Found the entrances on the south slope, all sealed up. Where are the other 2, are they on the north slope of the hill?

    5. Gary McCulloch says:

      Been up today, 1 entrance is open. Now located all 4. The ww2 bunker and radio station

    6. Ang says:

      Hi Johnny
      I’m here and looking for the access tunnel. Any way you can send me coordinates please?

  8. Sam c says:

    I have been 3 times over the last 3 weeks and I haven’t found an open entrance yet

  9. scott andrews says:

    I know of a entrance that will not be secured yet . Pm me I will send you location

    UPDATED: !!!! Please stop e-mailing me. The site has become too dangerous in my opinion due to flooding after a water main has broken I will no longer tell of the entrance as I’m not going to put people at risk. Hope you all understand !!!!

    1. Sam says:

      Scott any chance to can get in touch? Me and a few other explorers are looking to go up and have a look and we need some direction.

    2. John Travers says:

      Location please, am very much interested

    3. Jasmin Lopez says:

      Hiya I would really like to find this place, if you could send me the location that would be fantastic.

    4. Chris says:

      Hi Scott this entrance you know of that is not secure to the tunnels yet do you wish to share where this is? Thanks

      1. Scott says:

        Anyone wishing to know entrance I’ll share not a problem but not publicly. Also please be aware this site is actually fairly dangerous once inside please if anyone is going you MUST wear protective clothing and footwear and be cautious.

        UPDATE: !!!! Please stop e-mailing me. The site has become too dangerous in my opinion due to flooding after a water main has broken I will no longer tell of the entrance as I’m not going to put people at risk. Hope you all understand !!!!

        1. The Urban Explorer says:

          Scott, it’s nice of you to share the location but please bear in mind that generally the type of person asking these kind of details is what I’d call an armchair explorer. They want a postcode, a coordinate, a pin on a map. Minimal effort exploring. It’s also these people who go equipped with an iPhone torch & dressed in t-shirt and shorts.

          The Naval Fuel Bunker is not a hard place to find. There’s plenty of information online. And even if people can’t be bothered to search for that, a good old fashioned walk on Portsdown Hill will uncover this “mystery” in no time at all. Explore!

          In other words, you did the “hard work” in locating your entrance, and it’ll be the lazy explorer that gets it sealed up!

          1. just some random guy says:

            Dear The Urban Explorer,

            Sharing ideas and thoughts will always lead us to progress. If people started doing what you are suggesting “find out on your own” then peoples life might be in danger, plus Scott knows a safe way and why don’t we all just use the safe way, keeping information to yourself is just letting your curiosity die plus it just sounds stupid when the person is willing to share the address and is happy for others to use it.

    5. Tommy W says:

      Message me the location please bud been searching for this place for nearly a week 😂

    6. Sam Rahman says:

      Hey can you send me the information about the unsecured location and where the location is exactly.
      My email is

    7. Bleu says:

      Hi I’m on my way and need to know how to get there

    8. warren says:

      Hello Scott

      I would love to see this fuel bunker it has been on my list for a while now I know one entrance got sealed please email the entrance

    9. SammyG says: I’d like to know of the location if it’s still open :)

    10. Mac says:

      Want to go there today could someone send me an unsealed location? Thank you

    11. James Adams says:

      Where abouts is the site and where is the entrance I’d love to check it out.

  10. Dan says:

    Unfortunately all entrances have been welded shut with a big steel bar. We went down last Sunday and no way in. :/

    1. Paul says:

      Did you only try the 2 fronts or did you try one of the other 2?

      1. Jonesy says:

        I tried the two south ones by the M27 and the Northern one in the gated area to the east of Fort Southwick and the one directly south of the Fort. All are sealed.

        1. paul says:

          May be able to access. Shall let you know 😉

      2. Dan says:

        I went to the top left one on top of hill. And went to the two big doors by tunnels. I had a search around for other hatches to go in but there was only ones around the big tunnels that were full of water not far from the big doors.

        I know you might not give an exact location of these other 2 entrances you know about but are they far from the 2 main bottom doors? and what ish direction? would be slightly helpful. if wanna email me instead. I would appreciate any direction with it. Thanks

  11. Todderic Pritchard says:

    Is there any more entrances any one has found?

    1. Alex Rhodes says:

      There is only two entrances to the tunnels. Both very much sealed.

      1. The Urban Explorer says:

        Four, actually… *wink, wink*

        1. John says:

          Please can you tell me where to find the entrances!

        2. Alex Rhodes says:

          Cheeky. I mean there’s only two that can be “humanly” opened. but sadly now thats not the case anymore for any of the four. Luckily I have experienced being down there before :D

          1. The Urban Explorer says:

            Aaaah, you’ll be surprised by the local chavs’ resolve. Keep checking.

            1. John says:

              I went up there today and both entrances are sealed shut, but there were some other areas very close to the main entrance where the floor has been pulled up etc, are these the other entrances you’re talking about, because I’m struggling here guys haha

            2. Josh holton says:

              Is there a postcode?

            3. Daniel says:


              I see the new YouTube video, one was flying a drone down there, he did ok. Then one went somewhere on a rope and that went a bit wrong. Say no more. Would do but not local, never been there and a long way to go and fail. Anything please. Can be done as just has.


              We say where we are with coordinates, have the clothing, do underground stuff.

              Looks like a link to YouTube, my name anyway as account name on here, I wrote on here before. Must have.

        3. Simon says:

          Hi, I would like to know how to find the entrance unsealed

    2. scott andrews says:

      Yes I know of a way in that has been forgotten

  12. Sabercorn 1966 says:

    Went to site last Tuesday 24-10-17, all four entrances still sealed

  13. Jordan says:

    Entrance is now fully sealed up with concrete and a steel beams unfortunately

    1. John says:

      There is more than one entrance, Jordan.

      1. Daniel says:

        Went today and all four entrances are sealed.

  14. Danny Kelly says:

    Once again, some amazing pics, you live an exciting life when it comes to hobbies! Keep them coming – Thanks

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