Site Records


Site Name: Area Combined Headquarters Chatham & HMS Wildfire
(C in C Nore, RN & AOC No. 16 Group, RAF Coastal Command)

Cumberland Road
Chatham, Kent
OS Grid Ref: TQ771693

Sub Brit site visit 16th February 2008

[Source: Bob Jenner]

ACHQ Chatham
At Chatham (C in C Nore) a temporary ACHQ location unknown, but probably the newly built RAF No 16 Group HQ, camp and W/T station in Black Lion Fields, just to the southwest of Medway Road camp, was deemed suitable for emergency use until a permanent underground bomb-proof tunnelled ACHQ was completed in the chalk hill west of Admiralty House and to the south of the 'Lower Lines', an extension of the 'Great Lines', a series of dry moats built to defend the Chatham Dockyard. This project was contracted to Messrs Francois Cementation Co Ltd, the same company that built the Ramsgate Tunnel Shelters.


The ACHQ plotting room in WW2 - the wall maps seen from the viewing platform.

Whilst the tunnels were being constructed (22nd May 1939) the Civil Engineer in Chief (CE in C) at the Admiralty ordered that the floor of the Plotting Room be lowered by 2.5 feet, for better observation from the cabins (this being the approximate height of the plotting tables). The cost of the HQ was borne by the 3 services, against Vote 10 funding according to the amount of space allocated: RN 51%, RAF 45.5% Army 3.5%.

When built in December 1939 the HQ was designed to accommodate 60 officers and 90 ratings/other ranks of both services. By

November 1940 this had increased to 63 officers and 119 ratings/other ranks, an increase of over 20%. Space was forever at a premium. No sleeping facilities were originally provided but rest rooms and a small galley (kitchen) was.

The majority of the personnel were the Commanders, Chiefs of Staff, Staff Officers and advisors together with signals and communications teams and the ubiquitous GPO (BT) staff. Both services had Wireless Telegraphy (W/T) facilities within the HQ.  Two large wooden masts were on the surface above the HQ with the main Nore W/T station some one and a half miles away, north of the river Medway at Beacon Hill, Chattenden. This station was used between 26th March 1970 and 17th June 1970 to ‘jam’ the pirate radio station 'Radio North Sea International'

Beacon Hill W/T Station - Photo by Nick Catford
on board the 'Mebo 2' off Frinton-on-Sea. The plotting duties were mainly carried out by WRNS although there was a full RAF presence. The Defence Teleprinter Network (DTN) terminal for the entire Chatham area was now located within the new HQ.

The ACHQ was constructed of steel mine hoops under corrugated iron sheeting with interior panelling, the plotting room being much larger with 40’ diameter steel segments similar to the London Underground. The floor level of the tunnels entered the plotting room at first floor level, requiring steel stairs at each end to gain access to the plotting floor, which was effectively in a pit.  A viewing platform overlooked the plotting table at the eastern end. The plotting room originally had three glass-fronted cabins at floor level, which became raised when the floor was lowered. These cabins now overlooked the plotting table and the vertical map boards opposite.

Photo:A view of the plotting room in WW2 looking east. Two officers are standing on the viewing platform discussing the plot. Note the telephone PMBX in the background under the stairs, also the cabin shown has no desk under the window.

As a protection against blast, no tunnel had a direct line of sight from one end to the other, corridors moved from one side of the tunnel to the other and the one tunnel with no corridor (Signals and Teleprinter Rooms) had an office blocking the direct line. Each of the entrance tunnels also had a bend in them with an anti-gas airlock before entering the HQ. A ‘Lamson’ pneumatic message transmission system was also installed with a control room in Room 3 supplied with pressurised air from a pump room located at the bottom of the emergency exit and air supply shaft. Eight pairs of tubes have been found at the ACHQ, those rooms identified with a terminal were (original numbering): Room 42 Cipher Room, Room 43 Signals Office, Room 49 Organisation Office, Room 54 Cipher Staff Office, The Plotting Room and Admiralty House on the surface (well within Lamson range). The last two terminals remain unknown. As built, only chemical toilets were provided requiring a long and odorous emptying task.



Access to the complex was by way of 2 main entrance tunnels, the southern one from a small Nissen hut, within Medway Road Camp, itself off a private naval road leading to Admiralty House, the Naval Barracks (HMS Pembroke) and the Dockyard. This entrance was completely rebuilt during reconstruction work in 1957, which required the WRNS to enter via the Admirals’ entrance where an armed sentry was posted. This, the northern entrance, was from the dry moat of St Mary’s Barracks via a stairway, still

WW2 Main Plot looking west
extant, from the corner of the formal garden of Admiralty House. There was an emergency exit from the western plant area of the HQ, via three 20’ ladders, that went up one of the two vertical air shafts that served both ventilation rooms and provided an exhaust for the emergency generator. This exit emerged in the dry moat to the west of the northern entrance.

Photo:View of the plotting table in WW2 seen from the viewing platform

After the war had ended the ACHQ, complete with a RAF component now accommodated in Anson Block of the naval barracks HMS Pembroke, continued to function with the clearing of both enemy and allied minefields being a major concern and still later conducting NATO exercises in the area.
In 1956 the Nissen hut entrance was replaced by a small brick building, although the adjacent large 24 foot Nissen hut was retained for recreational purposes. In 1961 the Nore Command and the title C in C was abolished, the Admiral Superintendent of the Dockyard (Chatham) assumed the role and title of Flag Officer, Medway. With the reduction of responsibility and area, the underground ACHQ was closed in 1962.

Click here to continue the story of the Area Combined Headquarters Chatham & HMS Wildfire

[Source: Bob Jenner]

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