Room 40

Room 40 did not exist when war began at midnight, August 4, 1914, but the cable ship Telconia took the first relevant act in its birth. On august 5, in the North Sea off the German port of Emden, The Telconia severed five German telegraph cables that run through the English Channel to the world beyond. This led Germany to rely heavily on wireless telegraphy for rapid communications. The British Admiralty’s signals intelligence stations began to intercept German wireless messages and soon recognized the need for a formal cryptanalysis organization. Henry F. Oliver, the Director of the Intelligence Division, enlisted his friend Sir Alfred Ewing, Director of Naval Education, to organize a code breaking unit. Thus, from humble beginnings was born one of the most successful intelligence operations in history which made important, if not decisive, contributions to Allied victories in the First World War.
The initial recruits were fluent in German but knew very little about codes and ciphers. They were getting no where with the German cryptograms until the fortunes of war turned in their favor. Within twelve weeks, three important German naval codes came into their possession. The first, used for major operations, was turned over in mid-October by Britain’s Russian ally after it was recovered in late August from the grounded German cruiser Magdeburg off Estonia. The second was a German merchant marine and naval code from the German- Australian steamship Hobart. Finally, in December, came a German code used by flag officers (admirals), the most fortuitous catch of all. This code had been among secret papers tossed overboard in a leaden box from a German destroyer going down in the North Sea.
With these three codes in hand, Room 40 made dramatic progress. Before long the decoders could read much of the German navy’s signal traffic which helped them to keep track of the High Sees Fleet and locate menacing submarines. Success brought a greater recognition of need at high...