Cold War Sites

Fort Southwick COMMCEN

  Created 26-04-2002   Last update 27-03-2011

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The use of Fort Southwick as a Royal Naval (RN) Communications Centre (COMMCEN) can be split into three different entities and these will be discussed in the following order:


  2. The RN underground COMMCEN

  3. The RN above ground COMMCEN

The WWII underground UGHQ underneath Fort Southwick was finally closed in 1949, then reopened again by the Royal Navy during the 1956 Suez Crisis when it was refurbished. More permanent use was made of the tunnel complex in the early 1960s Cold War era as the Defence Teleprinter Network of the NATO Communication Organisation and as a Communications Centre - COMMCEN - for the Royal Navy. The NATO function was moved to Northwood in 1968. In 1974 the tunnels were finally abandoned when an above ground COMMCEN was built on the Parade Ground of the Fort. This was closed in 2001 when the COMMCEN function was transferred to the Portsmouth Naval Base.

During the Cold War era Fort Southwick was classed by the Soviet Union as a 'Category A target'  and consequently had two 1 megaton thermonuclear weapons assigned to it - one primary weapon and one as a back-up.


Aerial photo site location     Panoramic photo site location

Google Earth Aerial View

Grid Ref SU628068


Defence Teleprinter Network of the 

NATO Communication Organisation

During the cold war era of the early 1960s  the WWII underground tunnels of Fort Southwick were re-used as a relay station for the Defence Teleprinter Network of the NATO Communication Organisation. Although a secret installation, the NATO flag could be seen flying from Fort Southwick during this occupation.

It received multi addressed messages from the Admiralty at Whitehall and NATO HQ in Europe, and split and relayed the messages to various Naval authorities as necessary. Rows of teleprinters chattered away day and night, and punched tape hung everywhere. Each teleprinter machine had a print head attached to it through which the punched tape was fed. The head read the tape and operated the machine, although it could be over-ridden by the normal keyboard. Each machine had several strips of tape hanging from bull-dog clips awaiting feeding into the machine as soon as the previous message had gone through the head, and operators wandered up and down the rows of machines, armed with a clipboard and wearing tapes around their necks, feeding the machines, logging and retrieving sent tapes, and filing them away. Others would be intercepting inward message tapes, reading the multi-addressed heads, and redistributing the tapes with individual addresses added, to the appropriate machine for onward transmission. Each shift at the Commcen was manned by a couple of MoD civil servants and half a dozen matelotes and it operated around the clock.

Interestingly a former escape tunnel was used as an entrance by the staff to avoid having to tread the 149 steps from the main entrance inside the Fort, and this was manned at shift changeover by the MoD Police.


The following is an extract from an e-mail I have received from former personnel:

Congratulations, a very well put together site. I was particularly interested in the Fort Southwick tunnels because in the mid 1960s I was watchkeeping in the communications centre in these tunnels. I was an R.N. Leading Radio Operator on Commander-in-Chief Portsmouth's staff, and we manned the Defence Teleprinter Network set up in the 
WWII tunnels. This was a relay station for the NATO communications organisation... 
...We lived in the Victory barracks in Queen Street, and were transported up to Portsdown at watch change over times by naval transport. We used the lower tunnel entrance (probably why you saw lights there) which was manned by an MOD Policeman as this avoided the 149 steps! If someone had to arrive/leave part way through the watch the stairs up to Fort Southwick had to be used, and transport arranged to pick up/set down in the Fort grounds.
It's probably not generally known that the tunnels were used in this way during the cold war period. Thanks for bringing these memories back.


Brian Cave - ex RN. L.R.O.(T) SM - April 2002

Escape portal used as entrance by Commcen staff

This was the entrance used by the staff of the NATO Commcen.



RN Underground COMMCEN

The underground Royal Navy COMMCEN was established in the old WWII UGHQ tunnels in the 1956. During the early 1970s it became apparent that the cost of maintaining and refurbishing the tunnels was becoming prohibitive. Also the Fort Southwick underground COMMCEN was considered to be a fire hazard after a fire in a similar installation at RAF Neatishead. In 1974 the tunnels were closed when a new above ground COMMCEN was built on Fort Southwick parade.


Bob, with your excellent site in mind I dug out some photos you might like to use. They are not classified and you can use them as you see fit.


I have lots of very good memories of Fort Southwick, as I served first in the underground COMMCEN as a Leading Hand (Watch Supervisor) for two years, and then many years later as a Warrant Officer in the new above ground COMMCEN.
I also spent 2 years working on the staff of Flag Officer Third Flotilla (Aircraft Carriers and Amphibious Ships) in the offices across the road from Fort Southwick.


Alan Murchie ex WO (RN) - March 2011

DTN Room

NEW - 27-03-2011

The NATO Defence Teleprinter network (DTN) is already described on your site (see above). The bays in this tunnel connected to all shore bases in the Portsmouth Command area, i.e. HMS Collingwood HMS Dryad, HMS Dolphin etc by direct GPO PW (private wire) connection.

Photo: Alan Murchie

Ship Room

NEW - 27-03-2011

The Ship Room 1975. Mostly only one bay was used. For LCN (local command net) a simplex Morse net used for ships in and around Portsmouth Dockyard. Call sign MTN.

Photo: Alan Murchie

Stairs to exit

NEW - 27-03-2011

North East stairs leading to the the exit.

Photo: Alan Murchie


NEW - 27-03-2011

Disused tunnel spur. The sign on the wall was one of three salvaged by the author (Bob Hunt) and the Fort Southwick Manager shortly after the sale of the fort. It's much heavier than it looks and I lugged it all the way to the surface up the stairway. It dates from WWII as not all the stairways and adits were open during the Cold War era.

Photo: Alan Murchie


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