Authors: Erik Larson
T
HE DEPARTURE OF
W
ALTHER
S
CHWIEGER
’
S
U-20
WAS
watched closely—from afar.
In London, two blocks from the Thames and adjacent to the parade ground of the Horse Guards, stood a five-story building with a facade of pale stone and whiskey-colored brick. Familiar to everyone in the Admiralty, the structure was known, for short, as the Old Building, or, for shorter, O.B. Far less familiar was a secret operation located along one of its corridors in a group of offices centered on Room 40. Here resided “the Mystery” or “the Holy of Holies,” its function manifest only to its staff and to a coven of nine senior officials, including First Lord Churchill and Adm. Jacky Fisher, who by April 1915 had reentered the Admiralty as First
Sea
Lord, Churchill’s number two. Fisher was seventy-four years old, three decades older than his chief.
Every day, the watchkeepers in Room 40 received hundreds of coded and enciphered German messages that had been intercepted by an array of wireless stations erected on the British coast, and then sent to the Old Building by land telegraph. Germany had been forced to rely almost exclusively on wireless communication after Britain, in the first days of the war, had followed through on its 1912 plan to cut Germany’s undersea cables. The intercepted messages arrived in the basement of the Admiralty building and were then relayed to Room 40.
It was the task of Room 40 to translate these messages into the King’s English, a process made possible by a series of nearly miraculous events that occurred in the closing months of 1914 and put the Admiralty in possession of three codebooks governing German naval and diplomatic communications.
By far the most important, and secret, was the German navy’s SKM code, short for
Signalbuch der Kaiserlichen Marine
. In August 1914, a German destroyer, the
Magdeburg
, ran aground and was cornered by Russian ships. Exactly what happened next remains unclear, but one story holds that the Russians found a copy of the codebook still clutched in the arms of a dead German signalman whose body had washed ashore after the attack. If so, it was probably the codebook that killed him: it was large and heavy, 15 inches by 12 inches by 6 inches, and contained 34,304 three-letter groups used to encode messages. The letters MUD, for example, stood for Nantucket; Liverpool was FCJ.
The Russians in fact recovered
three
copies of the codebook, presumably not from the same body, and in October 1914 gave one to the Admiralty.
The codebooks were invaluable but did not by themselves reveal the contents of the intercepted messages. Their German authors used the volumes to obscure the original plain-text messages but then subjected the encoded versions to a further scrambling through the use of a cipher. Only holders of a cipher “key” could divine the underlying text, but possessing the codebooks made the whole process of solving the messages far simpler.
To exploit these treasures the Admiralty established Room 40. In a handwritten directive, Churchill set out its primary mission, “to penetrate the German mind,” or, as one of the group’s key officers put it, “to extract the juice.” From the start, Churchill and Fisher resolved to keep the operation so secret that only they and a few other Admiralty officials would ever know it existed.
Equally mysterious—though unintentionally so—was the matter of who actually managed the group. On paper, at least, it reported to Adm. Henry Francis Oliver, the Admiralty’s chief of staff, a man so tight-lipped and reticent he could seem almost mute, and
this—given the British navy’s predilection for nicknames—ensured that he would be known forever after as “Dummy” Oliver.
Within Room 40 itself, however, management of day-to-day operations fell largely, if informally, to Cdr. Herbert Hope, recruited in November 1914 to bring naval expertise to the interpretation of intercepted messages. His savvy was badly needed, for the group’s staff were not navy officers but civilians recruited for their skill at mathematics and German and whatever else it was that made a man good at breaking codes and ciphers. The roster came to include a pianist, a furniture expert, a parson from northern Ireland, a wealthy London financier, a past member of the Scottish Olympic hockey team, and a dapper operative named C. Somers Cocks, who, according to one early member, William F. Clarke, was “
chiefly remarkable for his spats.” The unit’s women—known as “the fair ladies in forty”—served in clerical roles and included one Lady Hambro, wife of a prominent financier, who according to Clarke startled everyone at one of the group’s annual dinners by smoking a large cigar. Wrote Clarke, “
It was the best of jobs and we were a happy band in those days with the best possible of chiefs in the person of Hope.” Hope was modest and retiring, and a skilled manager, Clarke recalled, and “all of us became deeply attached to him.”
Hope’s authority was recognized outside Room 40 as well, much to the displeasure of Dummy Oliver, who was
said to be obsessed with controlling who saw the deciphered intercepts and what was done with the information they revealed. When First Sea Lord Fisher made his initial visit to Room 40 and saw firsthand what the group was doing, he ordered Hope to bring him the latest intercepts in person, twice a day.
Hope also provided intercepts directly to another official who, of all those privy to “the Mystery,” had perhaps the greatest appreciation for the value of its secrets: Capt. William Reginald Hall, director of naval intelligence. It was Hall who had recommended that Commander Hope, then a member of his intelligence division, should be transferred to Room 40. Despite being chief of naval
intelligence, Captain Hall had no direct control over Room 40—as of early 1915 his intelligence division and Room 40 were separate entities—but his name more than any other would come to be associated with its achievements.
Hall was forty-four years old, and a former warship captain. He became director of naval intelligence in November 1914, filling a post once held by his father. He was short and brisk, with a face full of points and angles and a prominent bill-like nose, all of which gave him the look of a woodpecker in a captain’s cap. This was reinforced by a neurological quirk that caused him to blink rapidly all day long and that earned him his own naval nickname, “Blinker.” One of his most ardent admirers was America’s Ambassador Page, in London, who in a letter to President Wilson heaped praise like a man in love. “
I shall never meet another man like him,” Page wrote; “that were too much to expect. For Hall can look through you and see the very muscular movements of your immortal soul while he is talking to you. Such eyes the man has! My Lord!”
Hall delighted in the gamesmanship of war and was said to be utterly ruthless, albeit in an engaging way. His secretary, Ruth Skrine—later to marry and bear the wedded name Mrs. Hotblack—recalled how one acquaintance had described Hall as being part Machiavelli, part schoolboy.
The Machiavelli side “could be cruel,” she said, “but the schoolboy was always round the corner, and his love of the dangerous game he, and all of us, were playing would bubble out, and the fun and hazard of it all would fill him with infectious delight.” He was, she said, “uncannily quick at sizing up a man.” When contemplating some new escapade, she recalled, Hall would rub his hands together, “grinning like a crafty little French Abbé.”
I
T WAS A
vital game, in which Room 40 gave Britain an edge of inestimable value at a time when the war, far from concluding quickly, was expanding everywhere, with Germany ascendant. Battles raged in Russia, Austria, Serbia, Turkey, and Asia. In the
South China Sea a German torpedo boat sank a Japanese cruiser, killing 271 men. In the Pacific, off Chile, German warships sank two British cruisers, drowning 1,600 men and delivering a blow to Britain’s pride and morale,
the empire’s first defeat in a naval battle since the War of 1812, when a British naval force on Lake Champlain had been defeated by the fledgling U.S. Navy. On New Year’s Day, 1915, a German submarine sank the British battleship HMS
Formidable
, for a loss of 547 men.
British warships nearby were forbidden to rescue survivors, in accord with the policy set up after the
Aboukir
disaster.
The war had grown darker and had sired new tactics for killing. German warships shelled the English coastal towns of Scarborough, Whitby, and Hartlepool, injuring over five hundred people and killing more than one hundred, most of them civilians. The dead in Scarborough included two nine-year-old boys and a fourteen-month-old baby.
On January 19, 1915, Germany launched its first-ever air raid against Britain, sending two giant zeppelins across the Channel—“zeps,” in newly coined British slang, progeny of Count Ferdinand von Zeppelin. The raid caused minimal damage but killed four civilians. Another raid followed on January 31, during which nine airships flew as far as Liverpool, along the way sending terrifying shadows scudding across the landscape of Jane Austen’s
Pride and Prejudice
.
And then came April 22, 1915. Late afternoon, near Ypres; bright sunshine; a light breeze blowing from east to west. The Allied trenches in this sector, or “salient,” were occupied by Canadian and French forces, including a division of Algerian soldiers. The opposing Germans launched an offensive, which as usual began with shelling by distant artillery. This was terrifying enough, and the French and Canadians knew by experience it was a prelude to a head-on infantry attack across no-man’s-land, but at about 5:00
P
.
M
. the look of the battlefield abruptly changed. A gray-green cloud rose from the German side and began drifting across the blasted terrain as German soldiers opened the valves on six thousand tanks filled with over 160 tons of chlorine gas arrayed along
a four-mile stretch of the front—the first ever use of
lethal
gas on a battlefield. As the gas reached the Allied side, its effects were immediate and terrible. Hundreds died at once; thousands ran from their trenches in a panic, many having experienced exposure that would kill them later. Their flight opened an eight-thousand-yard hole in the Allied line, but the effect of the gas attack seemed to surprise even its architects. German soldiers wearing respirators followed the gas cloud, but, instead of surging through the newly opened gap for a decisive victory, dug a new trench line and stayed put. Their commanders, intending mainly to test the gas, had not assembled the necessary reserve forces to take advantage of the opening in the line. Two thousand Canadian soldiers were killed, suffocated as fluid filled their lungs. Wrote one general, “
I saw some hundred poor fellows laid out in the open, in the forecourt of a church, to give them all the air they could get, slowly
drowning
with water in their lungs—a most horrible sight, and the doctors quite powerless.”
But these cataclysms played out on land. Where Room 40 promised to give Britain the clearest advantage was in the battle for control of the seas, and there Britain’s strategy had undergone a change. Its centerpiece remained the destruction of Germany’s fleet in battle, but the Admiralty gave new weight to interrupting the flow of war matériel to Germany and to combating the growing U-boat threat to British commerce. The Admiralty also harbored the persistent fear that Germany might attempt a full-scale invasion of Britain. Clearly any advance warning of German naval actions would be of critical importance.
Room 40 began providing such intelligence almost at once. From November 1914 until the end of the war, according to the group’s William Clarke,
“no major movement of the German Fleet could take place without the Admiralty knowing about it some time in advance.” The information was detailed, right down to the movements of individual ships and submarines. But such detail raised a quandary. If the British navy acted in response to every foretold movement of the German fleet, it risked revealing to Germany that its codes had been broken. In a secret internal memorandum,
Admiral Oliver wrote that “
the risk of compromising the codes ought only to be taken when the result would be worth it.”
But what did “worth it” mean? Some of the men within Room 40 contended that much useful information was stockpiled and never used because
the Admiralty staff—meaning Dummy Oliver—had an obsessive fear of revealing the Mystery. For the first two years of the war, even the commander in chief of the British fleet, Sir John Jellicoe, was denied direct access to Room 40’s decrypted intercepts, although he would seem to have been the one officer in the fleet most likely to benefit from the intelligence they conveyed. In fact, Jellicoe would not be formally introduced to the secret of Room 40, let alone given regular access to its intelligence, until November 1916, when the Admiralty, sensing bruised feelings, agreed to let him see a daily summary, which he was to burn after reading.
The tight control over intercepts exercised by Chief of Staff Oliver was also a source of irritation for Room 40’s Commander Hope.
“Had we been called upon by the Staff to do so,” Hope wrote, referring to Oliver, “we could have furnished valuable information as to movements of submarines, minefields, minesweeping etc. But the Staff was obsessed with the idea of secrecy; they realized that they held a trump card and they worked on the principle that every effort must be made to keep our knowledge to ourselves, so as to be able to keep it up our sleeves for a really great occasion such as the German Fleet coming out in all their strength to throw down the gage in battle. In other words the Staff determined to make use of our information
defensively
and not
offensively
.” Commander Hope applied the underlines.
I
T WAS
tedious work. Hundreds of intercepted messages came chattering into the building’s basement every day, where they were placed in dumbbell-shaped canisters, which in turn were shoved into vacuum tubes and, with a satisfying
fwump
, launched up through the building. Upon reaching Room 40, the containers
tumbled into a metal tray with a clatter that “
shook the nerve of any unwitting visitor,” according to one of the group’s code breakers. The noise of these arriving messages was especially hard on the men assigned to the night watch, who took turns sleeping in a bedroom that connected two larger offices. They endured an additional hardship: mice. The rodents infested the bedroom and late at night trotted over the faces of the sleeping men.