Portland Naval Communication Headquarters

Portland Naval Communication Headquarters is an underground naval headquarters and communications centre on the Isle of Portland, Dorset, England. The headquarters is situated at the rear of Portland Harbour's dockyard, close to the inner breakwater arm. As with other historical sites within the proximity, such as East Weare Battery, East Weare Camp, East Weares Rifle Range and breakwater defences including Portland Breakwater Fort, the headquarters remains on private property of Portland Port Ltd, and has not been opened to the public.

History
The strategic importance of Portland's Naval Base and Dockyard during the rise of Second World War was fundamental, and in 1940 it was decided that an underground headquarters and communications centre should be constructed. The decision was to build two sets of tunnel entrances deep into the hillside at the back of the dockyard, and this would lead to a connection of underground rooms based around a central ring. Engineers continuously built the network of tunnels, almost a miniature township into the hillside, over the year and the headquarters was completed by 1941 with Portland acting as a sub-command of Commander in Chief, Portsmouth at Fort Southwick.

The two pairs of entrance tunnels, would join up to form single tunnels about twenty yards into the hillside. This junction featured toilets and washrooms, whilst a tiny guardroom was added to the western tunnel. The twin tunnels then extended 150 feet further to two airlocks. The control centre was designed with a rectangular shape. A short branch on the south side was added to house the ventilator, heating plant and standby generator. The rooms built consisted of a Naval Operations Room, Staff Room, Military Plotting Room, Wireless Telegraphy Office, Signal Distribution Office, a Teleprinters Room, a Messengers and Telephones section, and an Office. After the initial centre was constructed, plans were made to extend it further, with the addition of further tunnels on the north side, however this idea was dropped and never came to fruition. In addition, an underground air-raid shelter was also built into the bank a short distance inside the entrance to the Dockyard. It was constructed with two entrances going into the same hillside as the headquarters, for about ten yards, and a cross passage still retains two lines of benches today.

With the allied victory of World War II, and the start of the Cold war, the communication centre would be relocated to the Portland Heights adjacent to the ROTOR Radar Station at the Verne - another underground site. This new centre was still in use up till the 1990s. With the original underground headquarters now abandoned, it remained on care and maintenance until 1952 when the decision was made to refurbish the tunnels, transforming them into a standby operational headquarters for Portland Dockyard in the event of a nuclear attack. The transformation removed all the original partition walls, whilst a completely new room layout was installed. During the 1952 refit, the majority of the internal walls were stripped out with new breeze block partition walls forming a number of small offices around the central ring structure. A breeze block wall has also been constructed down one side of the main access tunnels, presumably to enclose cables and ventilation trunking. The original Naval Operations Room and Staff Room was transformed into a Teleprinter Room, Plotting Room and Staff Office. The Wireless Telegraphy Office, Signal Distribution Office and Teleprinters Room were now a Signal Office and Coders, and another three Offices. The Messengers and Telephones section became a Telephone Exchange, and a Cypher Room, whilst the Military Plotting Room became a series of seven smaller offices.

Under the control of a Naval Officer in Charge (NOIC), the headquarters was never put into use, although it had a state of readiness within eight weeks if required. During the 1960s, with the formation of the Royal Naval Auxiliary Service in 1963, some of the rooms within the centre were occupied by the RNXS for a short period, however they would soon transfer over to offices within the dockyard. The headquarters then became abandoned in the late 1960s.

Modern state
In 2004, Nick Catford of Subterranea Britannica visited the site on 1 September 2004 and reported that tunnels remained in "extremely good condition" but generally damp, having been lined throughout with steel segments similar to those used on the London Underground, and possibly made by the same company. The tunnels were noted to have three different diameters, the main access tunnels and most of the rooms being 8' 6" in diameter, the naval operations room and adjacent staff room about 16' 6" in diameter and the tunnel on the east side of the central complex being 12' 6" in diameter. The majority of rooms within the headquarters were designed with secondary curved wood fibre board lining, although in places this had fallen away. The plant room had some standing water.

The tunnels as they remain today have been largely stripped of all original fixtures and fittings. The ventilation and filtration plant, including trunking and electrical control equipment is still in place with ventilation trunking running into some of the rooms. A remaining engine bed, made of concrete, indicates the position of the standby generator. Within the inside of the first entrance, some electrical switchgear still remains intact, fixed to the wall. The water closet pans and hand basins are generally still intact and undamaged.

By 2014, more ventilation ducts have rusted through and fallen from the ceiling, whilst a small number of tunnel linings have peeled away. Some standing water still remains in places. A makeshift storage yard now almost completely covers one of the tunnel entrances outside. The site, owned by Portland Port Ltd, has remained neglected, and still unseen by the public.