The Whitehall Deep Tunnel.

"Top priority was given to the completion of a Whitehall Deep Tunnel, which was intended to offer secure communication and access between these various strongholds and certain buildings were selected for strengthening, including the Farady Building in Queen Victoria Street and the steel framed building in Horseferry Road."
CWR booklet-Simkins p42

"In September [1941] it was agreed that the elements of the Air Ministry staff would move to the Horseferry Road at the end of the year. The following April the Chiefs of Staff and Sir John Anderson proposed that the GHQ Home Forces should also go to Horseferry Road. The construction of the extension of the Whitehall Deep Tunnel to this citadel was completed in August 1942 and GHQ Home Forces, had actually moved there by November."
CWR booklet-Simkins p50

Government departments under Broad Sanctuary and Great Smith Street. The tunnel was extended to Horseferry Road Rotunda. Churchill equipped the complex with Lamson Pneumatic tubes.
London Under London p18

Cabinet War Room, later known as The Cabinet War Rooms.

"The Hole in the Ground" at Storey's Gate Great George Street, Horse Guards Road and King Charles Street.
The building work started in 1938 but many modifications continued to take place throughout the war. Located in the western basement of the Government Offices formerly known as the New Public Offices, the steel framed building was build between 1898 and 1915. The fact that it was a steel framed structure was important as it offered better protection than the older Whitehall buildings and was conveniently close to Downing Street and the other ministries. Originally only intended to be temporary, the project became more complex and permanent as the situation in Europe became more dire and a war more likely. The committee of Imperial Defence (CID) at a meeting on the 4th May 1938 decided that the Cabinet and the Chiefs of Staff should be provided with a central War Room. At the end of mat Ismay was made responsible for the War Room and RN Commander Angus Nicholl the Naval Assistant Secretary to the CID inspected the proposed rooms in the basement, then in use by the Office of Works and used for document storage. On the 31st May they reported that the rooms were suitable and could be cleared of their contents and protected easily and unobtrusively. The go-ahead was given by the Chiefs of Staff to Ismay to supervise the project and on the 10th June he delegated the task to Hollis who was assisted by Eric de Norman, an Assistant Secretary in the Office of Works and Lawrence Burgis a member of the Cabinet Office. In late 1940 a bomb-proof shield was formed by filling the sub-ground floor above the basement with reinforced concrete. In the winter of 1940-41 a concrete slab 3 ft thick and reinforced with steel rails and tramlines was installed above the basement. It was extended to cover the courtyard rooms and the CWR annexe. The apron wall was also built. Chamberlain rarely visited, Churchill succeeded Chamberlain on 10th May 1940 and quickly made his presence felt. He formed a coalition government and a War Cabinet of five members. The CWR contained a BBC outside broadcast studio, mechanical ventilation system, gas filtration system and 6 lifts. A detachment of ten retired Royal Marines, including two corporals were organized to act as guards and general orderlies. Originally in 1938 the roof was only shored up with timber but in December the roof was reinforced with steel girders.
The work on PADDOCK at Dollis Hill continued for some time in parallel but later was given a lower priority. It was thought that if the position in London became untenable the Cabinet and CoS would move to the West Country at once, rather than a double move to the suburban citadel.
The Central War Room was opened up on 27th August 1939 and the map keepers, called up from their civilian occupations, began their first watch in the Map Room. Six years would elapse before the Map Room lights were switched off again.
In 1948 it was decided that certain important rooms be preserved for posterity and visitors were able to visit them by special arrangement.
The CWR were opened to the public in 1984.
CWR booklet - Simkins.

"The engineer was Brigadier James Orr who died in 1993. Awarded the OBE but due to the nature of the work was not given a citation."
Secret London - Duncan p44

The Cabinet War Room and Goodge Street Deep Shelter were linked by Lamson Tube document transportation system.
Spy's London - Berkley p46

The Admiralty Citadel. The Mall - Horse Guards Parade

...the Admiralty blockhouse in Pall Mall (sic) ...Churchill called it "The vast monstrosity which weighs on the Horse Guards Parade"
BtCS - Laurie p199

"...a tunnel runs from Buckingham Palace under the Mall to a massive underground citadel, known as Q-Whitehall, which lies 100 feet under Westminster and Whitehall and extends as far north as Holborn. Evidence for this includes a huge extractor fan just outside the Gent's loo at the Institute of Contemporary Arts - directly above the supposed site-which the ICA confirms is nothing to do with them. The ICA building is immediately opposite a huge top security fortress building, on the corner of the Mall and Horse Guards Road, which is generally accepted to be the service access to Q-Whitehall. It is also known that a tunnel connects Downing Street to a massive atom bomb-proof bunker constructed under the Ministry of Defence building in the early nineties at a cost in excess of £100 million. It is likely that this building connects directly with Q-Whitehall."
David Northmore,
London N6.
Extract from Guardian, Notes & Queries, April 2 1997

"There was an untidy, clattering bustle; hardly one of the small rooms had less than two telephone conversations going on; officers and civilians and 'secret ladies' moving about the narrow corridors with heavily labelled folders and dockets, teleprinter flimsies or illegible sequences of decoded signals. There was a smell of rooms never empty for more than a few minutes, usedall round the clock. The Citadel quarters were admirably clean. ventilated and warmed by the standards of those days, but cut off by twenty feet of steel and concrete from the fresh air of St James's Park and the Mall. Indeed, it was probably the best bomb-proof headquaters in London.
Six hundred yards away to the south in Storey's Gate, the Prime Minister might sometimes wonder during the Blitz whether a direct hit might not bring the Thames flooding into his basement shelter. Not so the hundred men and women of the OIC (Operational Intelligence Centre) working in the Citadel, described by Churchill in his memoirs as that 'vast monstrosity which weighs upon the Horse Guards Parade'. They had the assurance of safety from even a direct hit - and a bracing assurance it was - but for it they paid the price of complete exclusion from the outside world: no windows, on daylight, no sound of traffic or birds or wind, only the noise of the work being done. It was the engine room of NID (Naval Intelligence Division)."
Extract from:
"Room 39 - Naval Intelligence in Action 1939-45" by Donald McLachlan has a good description of the use of the building during the Second Worl War.

Montague House

Whitehall. Beneath the Ministry of Defence building. Codename FORTRESS.
The wine cellar moved to make way for citadel.
Secret London-Duncan p107
London under London-Trench & Hillman. p211

Horseferry Road Rotunda.

Two gasholders built c1877 and demolished in 1937. Rebuilt as a subterranean citadel, codename ANSON.

In use in 1967 by the ROC (Royal Observer Corps school).

"In 1941 the tanks were converted into two heavily reinforced underground strongholds each equipped to house several thousand Government officials in absolute safety from enemy attack for up to two to three months. These were joined by a tube railway to similar strongholds in Whitehall [Montague House] and the Mall [The Admiralty Blockhouse].
BtCS p199

"...the government received advance warning ....of attack by flying bombs and rockets."
In July and August 1943 plans were made to prepare the basement of the North Rotunda at Horseferry Road for possible use by the Prime Minister, his personal staff and a nucleus of the War Cabinet Secretariat. These quarters, codenamed ANSON, were ready on the 15th November but in February 1944 Churchill repeated that he had no intention of moving unless London suffered a scale of attack far worse than anything expected to date."
CWR-booklet-Simkins p60

The building is mentioned by Pevsner;
"Government offices, Marsham Street and Horseferry Road. The architect was Eric Bedford an association with Robert Atkinson and Partners, built 1963-71. A vast job with 450000 ft of office space for 3600 civil servants. 3 slabs 200 ft high and 5 connecting wings projecting to the street. The ground floors are on stilts."

Geological Museum,

South Kensington museum, underneath is the London Civil Defence citadel.

PADDOCK, Dollis Hill.

Click here to go to my PADDOCK page

Post Office research Establishment. Government citadel built for the War
PADDOCK was completed in June 1940and believed proof against 500 lb bombs. Only one War Cabinet meeting was held at PADDOCK on 3rd October 1940 but the ministers disliked it and the Dollis Hill citadel was only visited once more on March 1941.
Sir William Halcrow & Partners built Whitehall government tunnels, Post Office, deep shelters, PO railway, Victoria and Jubilee lines, raw water mains, most tunnels since the 30's.
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