The War Illustrated, Volume 9, No. 210, Page 141, July 6, 1945.
Many thousands of people stared in wonderment during the last four years at an enormous, fortress-like building erected at the back of the Admiralty in London, with walls eight feet thick and guarded by A.A. guns. Here is the first description of a visit to this mystery building, known as "The Citadel". It was the Admiralty's wartime home.
Through the vast Admiralty buildings in the Whitehall, winding round a labyrinth of passages, I was halted by my guide in front of two massive steel doors - rather like a ship's watertight compartments, with controlling wheels by which they are closed. "This is the Citadel", he explained, as an armed policeman came forward. We were "vetted", for even high Admiralty officials cannot wander through those secret rooms and passages willy-nilly.
Thirty seconds later I was in that "hide-out" - the building specially constructed so that adequate protection from air raids and other forms of enemy activity could be given to vital Admiralty departments, so that if the main buildings were rendered useless the work of directing the operations of the Fleet could be carried on.
We went down through air-locks to a cool, air-conditioned atmosphere. There was a clatter of teletypes, the buzz of conversation in the biggest telephone exchange I have ever seen; the glimpse of gold braid on the sleeves of high officers. But although my guide told me that 700 people, many of them girls, worked the clock round in three shifts, I could not realize that I was in the most important building in London - if not the whole Empire.
In the 156 rooms housing all those people were many of the Admiralty's secrets. I saw dozens of people handling messages to all ports of the world. "There is no place we cannot contact", said a senior member of the Admiralty staff. "We use from this hitherto secret place every known method of communication - teleprinter, radio, voice frequency, and for the not secret messages the telephone."
Up in the top of the building great dynamos have stood ready for five years to take over the task of giving life-blood to the Admiralty's radio, by which any ship on the high seas of the world can be contacted. They stood yesterday grim and silent. They have never been needed.
Every 24 hours 8,000 messages go out through the Admiralty's signals communication branch. "Not only do we see that these thousands of messages are correctly received or transmitted, but we see that they are properly delivered, and that often means 100,000 copies a day, using a ton of paper every 24 hours", it was explained.
In other rooms, teletypes chattered to all parts of the world, giving out thousands of words to the Fleet and the shore establishments. Then I was shown the true "holy of holies", the secret Fleet Information Room where the movements of every craft are plotted, and where the Naval Chiefs of Staff confer when they want an over-all picture of what is going on.
The Duty Captain showed me round the whitewashed walls transformed into maps, with plots of movements of hundreds of craft - no matter where a naval action is pending this rooms knows all about it. And deeper still is the Radio Room, in touch minute by minute with the outposts of the Empire. - R.G. Grant, in Sunday Dispatch