Portsdown Tunnels - Cold War - NATO COMMCEN

Cold War Sites

Fort Southwick COMMCEN

Created 26-04-2002 Last update 14-03-2006

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Introduction

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.

Communications Centre - 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.

NEW - 14-03-2006

This is a very unusual aerial photo of Fort Southwick in that it is taken looking south, towards Portsmouth. The new above ground COMMCEN is arrowed.

Photo: Jim Boswell

The COMMCEN situated on Fort Southwick's Parade was built in 1973-4. It was closed after its function was moved to Portsmouth Naval Base in 2001.

The building is not hardened in any way although there is an extensive air conditioning plant.

Plan of the 1970s built COMMCEN.

Reproduced from Subterranea Britannica website

From the entrance a corridor runs the entire length of the building. The rooms on the left were mainly used for operations: Commcen Ship Room, Traffic Hall, Computer Room and Crypto Workshop. Those on the right housed conference rooms, plant and services: UPS room, AC Plant Room, Standby Generator etc.

From Smudge RN:

...on the right down a short passage used to be a bit of a kitchen. This is where someone on the watch used to be conned into cooking the watch their night time food that was sent up from HMS Nelson [in Portsmouth Naval Base]. Normally it finished up being stew or corned beef hash which normally did the job

This was the main operations area: the Traffic Hall with the door on the left leading to the Commcen Ship Room. The small hatch that can be seen on the left led to the “Special Handling Cell”. This was usually manned by just one person whose job was to work with any higher than normal security signal traffic.

Photo interpreted by Smudge - RN

NEW - 14-03-2006

Jim Boswell (1995) checking the status of the computer on the engineering printer in the Traffic Hall (the same view as in the above photo). The special handling hatch is over his left shoulder. Jim worked in the Commcen on odd occasions from 1975 doing installation work and settled there in1994 until the move to HM Naval Base Portsmouth from where he retired in 2002.

Photo: Jim Boswell

NEW - 14-03-2006

Jim Boswell working on the Plugging Jackfield. All the lines in and out of the Commcen terminated on one half of the cabinet and all the local equipment on the other. This made it possible to patch any equipment to any line. The entrance to the Naval Digital Network is behind him. This was a digital network linking all the Commcens and other sites using routers that automatically used the best route and bypassed any parts of the system that were faulty . The phones on the right were the last ditch communications if all else failed.

Photo: Jim Boswell

Leading off from the room in the photo above is the Computer Room. The holes in the floor indicate where a Mainframe once stood. This was run in tandem with with another machine so if one went down the other took over There are acoustic panels on the wall and all sounds are deadened.

Photo interpreted by Smudge - RN

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