the d-day bunker

From the very first conference of the Anglo-American Allies held on the 31 December 1941 in Washington DC, the US committed itself to prepare for landings on the European mainland. Europe first. The Americans feared a Russian collapse and began planning Operation Round-up to invade northern France by April 1943 at the latest. However the British resisted being hasty especially after the disastrous raid on Dieppe in August 1942.  At an Anglo-American strategy conference in Quebec in August 1943 the Allies again agreed to the seaborne invasion of France, now codenamed Operation Overlord, and the Americans insisted that a provisional date of 1 May 1944 be set.

As well as hundred of airfields, barracks, jetties and even roads, an Underground Headquarters was constructed deep under Fort Southwick, high atop Portsmouth on Portsdown Hill. Over 1000 people were based above ground around the fort, at various headquarters associated with the planning for D-Day. These included the army and navy headquarters for the British/Canadian D-Day beaches, Second British Army and the Naval Commander Eastern Task Force respectively. An access ramp was built down into the east ditch (which still exists), where many of these personnel were billeted. Sat on the spoil from the tunnelling done below to hide its construction, covered by camouflage netting.

The underground workings at Fort Southwick were excavated by 172 Tunnelling Company Royal Engineers, miners from Wales and the North. Work was started on 16 February 1942, probably as a direct result of the Washington Conference mentioned above and the complex was completed during December 1942. The tunnels were about 100 feet beneath the surface. Air conditioning and gas filtration was installed as well as fresh water storage. Access was via 3 notorious staircases from within Fort Southwick - there was no lift.

The Bunker provided a bombproof, comprehensive Naval, Army and Air Force Operation Control and Communication Centre - call sign 'MIN'. The headquarters’ main role on D-Day was gathering information and coordinating the Allied naval forces. Reports from radar stations were crossed-referenced with messages from shipping to provide an accurate picture of what was happening in the English Channel. This information was then plotted on a large table map at the Fort, and was passed to the Allied commanders nearby at Southwick House. On the 6 June 1944 there were 700 staff working underground. 

Because of its D-Day connection, its existence was a very closely guarded secret, which still seems to persist even today.  Southwick House located in the village of Southwick a mile north from the Fort, was used as the headquarters for SHAEF (Supreme Headquarters Allied Expeditionary Force) although the actual HQ, on and for some time after D-Day, was a tent in nearby woods.

As part of the Fort Southwick UGHQ construction project, a secure underground radio station was also built in the Paulsgrove Chalk Pit. The concrete anchor blocks are still there used to secure the masts.

Two other back-up UGHQs were built, in case Fort Southwick was put out of action. The Bunker was "to be defended to the last man and the last bullet" and had explosive charges set to destroy it had it fallen. There were no fixed defensive positions, they no longer feared a German invasion.

The UGHQ complex was partly re-used during the Cold War as a Communication Centre. In 1974 a replacement COMMCEN was constructed on the Parade Ground.

The bunker was abandoned, broken into, pillaged and eventually stripped by the MOD.

In 2006, lights starting coming on, debris was cleared and there was a buzz of activity.

The bunker was alive!