By Nicholas, David
History Today , Vol. 57, No. 9
EVERYBODY NOW KNOWS that the Second World War was significantly shortened thanks to the team at Bletchley Park, Milton Keynes, who cracked the code of the German Enigma machine, enabling the British to overcome the devastating U-boat campaign in the Atlantic. But fewer are aware of the Royal Navy's huge success during the First World War in reading German naval codes.
At the start of the war, the Germans were operating three military codes. Within four months, the British were in possession of all of them.
The new-born science of reading enemy radio signals got started in a small room in the Admiralty, on the same corridor as the First Sea Lord's office. Room 40 was 24 ft by 17 ft and looked out on the inner courtyard, remote from the rest of the Admiralty. Over the course of the First World War, some 20,000 German messages were decoded by Room 40, the name by which the operation continued to he known even after the unit expanded beyond its four walls.
Just hours after war was declared, the British assigned the cable ship, Telconia, to cut the first of five German cables, which ran from Eraden, on the German-Dutch frontier, down the English Channel to France, Spain, Africa and the Mediterranean: a coup which forced the Germans to rely heavily on encoded wireless transmissions.
Wireless telegraphy was in use on all warships and many merchantmen in 1914. Through the foresight of a pre-war Director of Naval Intelligence, Rear Admiral Henry Oliver, the Royal Navy had a number of radio directional stations along Britain's east and southeast coast, which could pick up German naval radio messages. Oliver turned to a friend, Sir Alfred Ewing, a former Director of Naval Education, who began to assemble a group of scholars specializing in German affairs with the purpose of deciphering German communications.
But the effectiveness of Room 40 hinged on a series of strokes of luck. The good fortune came in the first week of the war. A German steamship Hobart was seized by Australians off Melbourne. Before the skipper could destroy it, the Australians confiscated a codebook, in use between German warships and merchantmen but which was due to be used by naval and shore bases, U-boats and Zeppelins.
The codebook did not arrive in London until October 1914. By then the Royal Navy had obtained an even more secret book from their Russian allies, who in August had collected three copies from the scuttled German cruiser Magdeburg which had run aground near the Gulf of Finland.
Early in December came a third piece of luck: a British fishing boat hauled up a lead-lined chest containing the secret papers of a German destroyer sunk off the Dutch coast six weeks before. This yielded the German code for communicating with warships overseas or with naval attaches. The Germans did not believe their codes had been broken. They were prodigious users of wireless transmissions and, indeed, had reason to be proud of the excellence of their transmitters. Their radio tower near Berlin could transmit to the Mediterranean, the Americas, Southern Africa and even as far as China.
Beyond such good fortune, key to the success of Room 40 was Captain--later Rear Admiral--Sir Reginald 'Blinker' Hall, appointed Director of the Intelligence Division in October 1914. An American Ambassador said of him 'Neither in fact nor fiction can you find any such man to match him. The man is a clear case of genius. All other secret servicemen are amateurs by comparison.'
Hall broadened his operation from just codebreaking to wider aspects of Intelligence. He helped Scotland Yard in tracking German spies. He established links with the censorship authorities, with the Secret Service and with the enforcers of the blockade against Germany.
Hall had a natural instinct for cloak-and-dagger work. As early as 1915, he was aware that the Germans were plotting with Sinn Fein, and it is claimed that the Rising against the British in Ireland in 1916 might have brought heavier fighting had it not been for his imaginative work. …