Naval Fuel Bunkers

  Created 25-08-2001   Last update 21-08-2021


Fuel Bunkers

page 1 of 3


 Fuel Pipeline


A book about the Fuel Bunkers is in the making.

For a preview click here


General history

These were built during the late 1930s as bombproof Naval Oil Reservoirs. I believe that three of this type were built in UK.  During the  1990s the extensive undergrowth was cleared away, the perimeter fence was replaced, and the site including the pipeline was decommissioned. This corresponds to the closure of other Royal Naval underground storage facilities such as the Invergordon oil depot, Copenacre, Hartham Park and Monk's Park. The site is listed in the MOD National Asset Register (see links for more info) as the Portsdown Oil Fuel Depot.  In the past, residents in the surrounding area have complained of strange underground noises.

The underground chamber contains nine 35 feet high concrete storage tanks, most of which are capable of holding 19,500 tons of Furnace Fuel Oil. There is also a large pumping station containing 2 pre-war pumps which were used to pump the oil to the oil fuel jetty in Portsmouth Harbour. The walls of the reservoir were made of concrete 22 feet thick, and no bomb produced during WWII was capable of penetrating this structure. At least 15 men died during the construction, usually due to rock falls. Many of the construction workers were Irish Catholics, and the last rites were frequently given inside the cavern; the priest seemed to be on constant call. 

The oil was needed as an emergency supply for British warships in case oil deliveries to western British ports were blockaded by the German Navy. The construction work was undertaken by Sir Robert McAlpine's construction company.


A note on Furnace Fuel Oil

Officially:  FFO Fuel, residual: Medium viscosity, boiler NATO Code No: F-82; Joint Service Designation: 75/50 FFO. This type of fuel was phased out by the Royal Navy in favour of diesel fuel in the late 1970s. The last ships to use it were the Leander class Frigates, the Falklands veteran aircraft carrier HMS Hermes, and the Royal Yacht - Britannia. For more about FFO click here.


Main Southern compound

A dedicated access road (Hillsley Road) was originally built to service this site, on the southern slope of Portsdown, which consists of two large portals 70 yards apart: the western 'pipe tunnel' and the eastern 'service tunnel' This road has now been incorporated into the Paulsgrove housing estate. A pipeline ran from here to the the Oil Fuel Depot at Forton Road Gosport five and a half miles away to the south. For details of the pipeline click here.

There is also a pipeline which runs to Fort Southwick, where there were holding tanks which held the oil for the heating system of ASWE. A connecting tunnel was thought to have been excavated in May 1942 as part of the construction of the UGHQ at Fort Southwick, but this now looks increasingly unlikely.

There have been news reports in the past concerning the underground workings in this area - see 'Hillsley Road - Legends & Mysteries'. 


Valve compound

On top of Portsdown to the west of Fort Southwick is a large high fenced Valve Compound, which is to the north and slightly to the west of the main Southern portals. This gave direct access to the pumping station below. The distance between the Southern portal and this site is 400 yards.


Northern compound

On the Northern slope of Portsdown the tunnel makes its final exit into open countryside. The distance between the Southern portal and this Northern portal is 500 yards. This site and the Valve compound mentioned above are built on two massive spoil heap plateaus which were camouflaged with grass and scrub.


With thanks to

Jeff, Ian Dunkley, Bazzer, Peter Crowson and Peter Cobb

 for their contributions.


 The following are extracts from e-mails received:
NEW - 21-08-2021
  Very unfortunate about the book, I would much rather read that than the drivel autobiographies that are endlessly being released. Could you not retry or try the PDF route again? That is assuming methods may have become easier for editing [They haven't]. I was looking forward to a different insight other than reading your website.

 In 2007 it's quite possible that Ged [Hallam] would have still been part of the secrets act, it was 2007 I first went up there after finishing a late shift, I could see the tunnel all lit up inside seeping from the mesh around the edge, which at the time was a black door. I guess I took a step too close because I set off an intruder alarm with a red flashing light and what can only be described as a weird nuclear alarm echoing down the tunnel, turned, ran and forgot about the steps I had just walked up. Ouch. It's a very confusing situation regarding the tunnels.

My parents have filled me with various stories of their escapades with the workers and site security for ASWE. Riding a moped that had been dumped outside the west compound up tunnel to reach the pump room ladder faster, Eric driving his car up the main tunnel and having to reverse it out to the 400 yards or so of aerial cable ran down into the complex so they could watch TV! They tell me of steps under the hill that literally opened up as a hatch on the hill, they are adamant it is not what they termed as angel steps inside the fuel bunker. Trying to get a clearer picture so I could locate such a thing is proving to be a slight pain because everything is so overgrown.

My mother did ask him about any potential documents, all logs etc had to be handed back in to the Navy and the Official Secrets Act signed. He mentioned the inspection points dotted along the pipeline so that you could go under them along with other tunnels that he said are now collapsed in. If I can retrieve some solid information on their whereabouts etc then I'll be sure to come straight back to you.

Paul - August 2021


NEW - 29-04-2012

I've just seen your website and your photos bring back many memories for me. I worked for Pritchard Security in the 1980s and had to look after them. It was awful cold damp and bloody eerie to say the least; walking round there turning time clocks etc for £2 an hour. Have you ever tried to walk the ramp there [the machinery ramp] that was a feat in itself, and Ged the stoker ....all coming back to me now, any way good site loads of memories.

Richard - April 2012


NEW - 29-04-2012

I was very interested to read your piece in the Portsmouth News last night regarding the Portsdown tunnels. My father was an engineer during the war working at the Gosport Fuel Depot responsible for maintaining the pumps that pumped the oil off the tankers into the storage tanks in the depot and from there to the reservoirs under Portsdown Hill. As a child of 9 or 10 years at that time I would on occasions, during the school holidays, go to work with him at Gosport and I remember once or twice he took me into the fuel tunnels under the hill and, on one occasion, we exited via a vertical shaft which came out on the top of the hill just east of the roundabout at the top of Portsdown Hill Road [the valve compound]. He told me that the tunnels were mined so that they could be destroyed  if the Germans ever invaded. [Yes they were: with two tons of explosives] My fathers name was Leslie Moffatt.

John Moffatt - April 2012


NEW - 19-09-2010

Having lived in the Portsmouth area all my life I was astounded to read your excellent web site. I knew about the fuel bunkers From 1961 when I was in the Fire Service as we carried out our BA training at this site. However our training records only Stated Portsdown and not where we had actually trained. We Were told not to speak about the site to anyone This is the first time that I have said anything as I signed accordingly. [The Official Secrets Act].

In my time in the Fire Service we were employed by the local Authority as Portsmouth City Fire Brigade, and not until the Reorganization of Local Authorities did Portsmouth merge with Hampshire and it became Hampshire Fire and Rescue. The headquarters and training centre based at Eastleigh. I would have thought that Portsmouth Fire Brigade records would have passed to the Portsmouth Records Office.

Anonymous by request - August 2010


NEW - 23-10-2009

My husband is very interested to read your site because he was born in1943 and brought up in Carlton Road and remembers all sorts of stories. His father told him that the men building the bunker and pipelines had to go in a decompression chamber when they came out because of problems with the Bends. Also that there were cornfields where Browning Avenue now is and that animals kept falling down what the local children called The Well.

He said he can remember the big blue RN Fuel tankers coming half way up Anson Grove to where there were big metal doors on the ground. They connected all their pipes etc and did whatever they did!! All the children used to go and watch. My husband assumed they were taking fuel but reading the information on your site it seems more likely they were putting it into the tanks. He said the men used to wipe the pipes with cotton cloths which the children took home to use as fuel for the fires (probably more likely took into the fields and made their own little fires)!. He also remembers light bulbs being thrown out from the tunnels ~ they had screw fittings which he said were very unusual then. He was around 7 or 8 at the time so it would have been late 1940s.

Jennie & Derek Penfold - June 2009


NEW - 23-10-2009

First let me say how much I love the site. Youíve done a tremendous job. I was born in December 1946 at St Maryís and we lived 7 Hill Road Portchester. My father was at that time employed by the Southern Electricity Board and had been all during the war years. I remember him telling me about the fuel bunkers by Fort Southwick and he always told me that they used to go in and out by what I see you call the Valve Compound. He always told me that he was responsible for all the cabling and wiring in the Bunkers when they were built.
When I was 6 or 7 our Sunday morning was a walk up over the hill to Southwick to the Red Lion (?) I sat outside with a bottle of pop and a packet of Smithís finest while Dad had his pint and then we would walk back in time for Sunday lunch. I remember him showing me a smaller tunnel half way down the hill which he always said was built as an escape route from the fort if it was ever needed. He said that there were two of them. I imagine that the construction of the M27 saw the end of those. I would guess that Dad had very probably seen most of the inside of the Fort at some time or other. Dad was also in the Home Guard but I donít know which unit. After the war he became a Special Constable in Portchester. I clearly remember him going out in the evenings in his uniform.

John Wade - August 2009


NEW - 07-09-2008

I used to live and my parents still do in Harting Gardens. Their back garden backs onto the alley way which is the old pipe line route just by location D in your photos in the pipeline section. When I was young, me and my friends used to play football on the field and used the trees right by where you took the photo of location D as the goal posts. I remember the inspection pit, it was just the other side of the bush with the red dog poo bin in front, and it was a rectangular checker plate piece of metal about 2 x 1 meters in size. At some point they filled it in with concrete and I can't remember if it was at the same time but the whole area just in front of the chain link fence of the school was dug up and then filled back in. I remember this well as it turned half of our football area to mud and rubble! We weren't happy. My parents told me that at some point in the 1980s all the houses that backed onto the alley way between location C and D tried to buy the parts of the alley way behind their houses. They were told they couldn't as it was now seen as a path and it would cause an inconvenience to people that were accustomed to using it. This annoyed them as the section between location C and Dore Avenue was sold off.

Adam Shepherd - September 2008



I worked for some years at the R.N. Oil Fuel Depot at Forton Rd. Gosport. During that time I made many visits to the Portsdown storage reservoirs.

The main tunnel (south west entrance) as the plan shows [see below], runs past the front of the reservoirs, and has a very slight incline, the drainage from the front of the reservoirs followed this incline to a pit in the SW compound which was emptied by tanker when full and taken to Gosport depot. When the tunnel passed the last (northernmost) reservoir it changed to a much steeper incline which made me puff to walk it, there was a solid door at the top [northern portal] but this was never closed, instead there was an iron barred gate this allowed the tunnel to act as a very efficient ventilation system. The prevailing wind blew in at the south entrance, past the pump room and reservoir entrances sucking fumes out of them and taking them out at the north. The pump room floor is about 6/8 foot lower than the main tunnel floor.†

...the main pumps at the Gosport depot were capable of pumping to Portsdown. The Bedenham pumps were installed as booster pumps and were not always used.†

...there is a lift shaft and a stairway which runs down from the top compound, [so called valve compound] these both open on to a platform which leads via a 90% turn to a ramp which runs down to the pump room, on the platform a door similar to a ship bulkhead door had been let into the concrete wall, behind the door was a room shaped like a small Nissan hut 15/20 foot long cut into the chalk and lined with some sort of hard board under a metal framework [This room was added during WWII and appears to be some kind of telephone exchange]

The pipeline ran under Fareham creek from Wicor playing fields area (Portchester) into Fleetlands Aircraft Repair Yard, close to Fleetlands jetty. It then turned south to the Bedenham booster pumps, from there it ran to the oil fuel depot Forton rd. Gosport following the military railway line which ran through Frater and Elson armament yards to Priddy's Hard. From there it ran under Forton creek into the oil fuel depot, there were no tanks between portsdown and the oil fuel depot. The main pumps, 2 for furnace fuel oil, 1 for diesel, were situated in the oil fuel depot, incidentally the pumps ran on D.C. current which was the power system used in Gosport when the depot was built. When the supply was changed to A.C. in Gosport an A.C / D.C. converter was installed in Clarence yard to keep the pumps supplied with D.C. power.

The oil was pumped from the oil depot, under Weevil lane, under Royal Clarence Yard to the oil jetty, which is now twice as long as it was originally built, it was then nearly always loaded into lighters which then delivered to ships in the dockyard. 

When the M27 was built the pipelines were re-routed under the motorway in a tunnel. 

Norman Beckett - July 2003



I read your site with great interest and having grown up close to the Oil Fuel Depot in Gosport. I started work as a JSA (junior storehouse assistant) in the Yard when I was 15 years old and by the time I was 18 I was transferred to the Oil Fuel Depot at Gosport, 1963. 

I can recall that at that time we were pumping FFO [Furnace Fuel  Oil] from Portsdown on a regular basis. At the end of one particular Friday I was told that I had to go and collect some oil samples that had been forgotten from the Pump Room on the Hill. I was given the keys to the depots new Vauxhall Victor F and I drove from Gosport to the top gate [west gate]. I had to unlock and then lock up each of the metal gates on the way down and to be honest I was absolutely petrified having been told some of the alarming stories by Paul Ferrier (the Storehouseman), Ted Wilden and other staff in the Depot.

 However I managed to curb my fears and carry on with the task in hand. This was to collect some oil samples and return with them to the testing laboratory in the Depot. I went right through the entire complex except for the access tunnel on the east side, exploring as you would!!! I even went to the north side gate, for which I didn't have a key. I think the most amazing thing about the Pump Room were the pumps, all gleaming Green, Red with highly polished brass and steel. A real credit to the engineers who maintained them. Then the long climb back to the top, all the time having to unlock and re-lock the gates. 

I must say that day was definitely a day to remember. Although after the walk home to Albert Street Mum said "Did you do any thing interesting today"? Worn out all I could say was "Not much Mum".

John McLeod, Storehouse Assistant, Oil Fuel Depot, Forton Road, Gosport 1963-65 - November 2003



It was about 20 years ago [1983] when I went down into the Fuel Bunkers. I was in the Fire Service at the time in Fareham. We had to go down as part of a Fire Service drill. It took a long time to get down to the bottom & even longer to get back up (we had on breathing apparatus for the purpose of the drill only).

When we arrived at the bottom there were three big sheds - like in a garden but a lot bigger. We understood that there were three shifts looking after the site each shift living in their own shed while on duty.
Each shed was fully kitted out for living in although I only went in one.

The bottom was huge, as big as a cathedral, no supports just a great big dome. Leading off from the centre were huge mouse holes (tunnels) they seemed to go on for miles!

I was told that the tankers berthed in Gosport on the oil fuel jetty at Clarence Yard and the oil was pumped up to the top of the hill via  pipes that went under the harbour.

Alan Scutt - Ex Fire Service - November 2003


Aerial photo site location     Panoramic photo site location

Google Earth Aerial View

Visit this site - Portsdown Walk No2


fuel bunker map

Map showing the fuel bunker surface layout.

Northern SU623072
Valve SU622069
Southern SU624066


fuel bunker plan

Plan of the Fuel Bunker. 

There are at least 2 miles of tunnel. The main Oil Tanks are 800 feet long and 35 feet high, and can hold 19,500 tons of Furnace Fuel Oil each.

Obtained from the PRO by Peter Cobb

Crown copyright


A Spoil heaps
B The Northern Portal
C One of the main fuel tanks in this case No 6
D A now demolished surface building which is thought to have been used during the construction of the Fuel Bunker
E The Valve Compound on top of the Hill. The plans say that a stairway leads down from here
F The pumping chamber
G B2177 road which runs across the top of Portsdown
H The southwest angle of Fort Southwick
J Fort Southwick Married Quarters - now demolished
K Southwest portal and pipe tunnel
L Southeast portal
southwest adit of the Fuel Bunker

Looking north in the southwest tunnel marked 'K' in the above plan. The guy in the photo is Leading Stoker Ged Hallam and the photo was taken in 1989.



Fuel Bunkers

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 Fuel Pipeline