Site Records

Site Name: Fort Southwick

James Callaghan Drive
Portsmouth, Hampshire
OS Grid Ref: SU628069

Sub Brit site visit 3rd December 2002

The UGHQ was completed in December 1942 and known as Portsmouth Naval Headquarters. It was designed as a conventional bombproof HQ for wartime use by the Commander-in-Chief Portsmouth containing a comprehensive naval operational control centre with associated communications centre and limited accommodation. An additional galley was provided in the main caponier which was accessed from the north-west stairs.

It was not, as is often stated, the headquarters of the Allied Commander-in-Chief 'D' Day Expeditionary Force. SHAEF (Supreme Headquarters Allied Expeditionary Force) which was located at Southwick House (now HMS Dryad) in Southwick village, a mile to the north of the fort. The Allied Naval Commander did, however, make full use of the UGHQ communications facilities for Operation 'OVERLORD' from his office at Southwick House. A radio transmitter linked from the UGHQ was located in the west demi-caponier and as part of the UGHQ a secure underground radio station was installed in tunnels excavated in the face of the Paulsgrove Chalk Pit a short distance to the south of the fort.

There are three main tunnels (110 yards in length) running parallel to each other with twelve cross passages (55 yards in length) providing office space, limited feeding facilities and some cabin and dormitory accommodation. In addition, two other tunnels and one cross passage were used as corridors and for emergency off-watch bunk sleeping.

The depth of the UGHQ varied according to the slope of the hill, but was in the region of 80-100 feet. There were two main entrances/exits. The eastern (179 steps) entrance was alongside the present CNH Plans Division Offices, whilst the Southern entrance, known as the South Adit was on the slope overlooking the harbour. Four other entrances, namely the Galley Tunnel (North west Stairs), the West Stairs, the Diesel Tunnel (later used as the main NATO Commcen entrance) and the Air Supply Tunnel could be opened for emergency evacuation.

Message decoding room - Photo from Sue Solly

Air conditioning was provided through anti-gas filters and the system could, if necessary, be operated as a closed recirculation circuit and 2 x 2,000 gallon tanks were provided for the exclusive use-of the UGHQ. The War Complement, including the above-ground staff, was in the region of 140 Officers and 480 ratings with six weeks supply of food available for the UGHQ. Under normal conditions ample above-ground sleeping and living accommodation was provided.

Officer sleeping accommodation was, in the main, provided by using caravans parked in the moat. During a state of 'alert' however, the underground feeding and accommodation facilities were activated. The cabins and dormitories, together with the bunks along the passage tunnels, were used for off-watch sleeping. At the end of World War II, the upper Fort was used by the HMS Mercury Signal School (1946-1948) for the training of Communication Branch National Service and Short Service ratings.

GPO carrier equipment room

The UGHQ was however sealed off; the intention being that it should remain dormant ready for any future emergency. Once the Signal School moved out the fort was placed under the jurisdiction of the Captain of HMS Dryad and manned, on a care and maintenance basis, by a RN Officer and a small civilian staff.

For further information and pictures of Fort Southwick click here

Return to Fort Southwick home page .................................
Gallery 1 Entrance to the fort and the barrack block ...........
Gallery 2 The parade ground, dry ditch & Chemin de Ronde
Gallery 3 Victorian gun emplacements .................................
Gallery 4 Victorian tunnels, magazines and caponiers ..........
Gallery 5 Underground Combined Headquarters ................
Gallery 6 Underground Combined Headquarters ................
Paulsgrove Quarry - Underground radio station..................
1974 NATO Commcen ....................................................

Home Page