First, a British submarine attempted to ambush the rendezvous between three U-boats and a supply ship in the Cape Verde Islands. Then a British prisoner of war admitted that, during the sweep of the Bismarck‘s supply ships in the summer, one of the victims, the Gedania, had yielded signals documents long thought destroyed. Finally, on November 22, another ambush of a supply ship and U-boats off St. Helena occurred.
Dönitz refused to wait any longer. Exactly one week later, he changed the bigram tables and made plans to deploy a new weapon in the cryptographic war, something the British had suspected was in development and feared was close to introduction, particularly after the capture of the U-570. When experts in the Naval Section had examined the lid of the smashed Enigma machine recovered from the submarine, they found the usual brown-washed label on the inside. This one, however, possessed a sinister difference: instead of a stamp bearing the moniker Schlüssel M3 to denote the three-wheel version of the machine, it read Schlüssel M4. For months, Bletchley Park had been picking up indications that something new and troubling was afoot—that a machine sporting a fourth rotor existed. Now they had the first concrete evidence that an improved version of the naval Enigma machine not only existed but was about to be issued to the deadly U-boat fleet. It was only a question of time before that would happen.
The four-rotor Enigma machine—really an improved three-rotor machine—was introduced by the German navy for its U-boats operating in the Atlantic on February 1, 1942. For over ten months the new machine left the British dangerously in the dark in terms of their ability to access U-boat communications in the most vital of all theatres in the Second World War, the Atlantic Ocean. That blackout presented an immense, almost insurmountable challenge to the cryptographers working tirelessly in Bletchley to gain a break into the new machine. (photo credits 4.8)
FIVE
SWIMMING WITH SHARKS
Of course as far as we are concerned here, pinching is the best form of cryptography.
—NIGEL DE GREY, ROOM 40 VETERAN AND DEPUTY DIRECTOR OF BLETCHLEY PARK
News of the four-rotor Enigma machine did not catch the British completely by surprise.1 In January 1941, John Godfrey had learned from a set of captured instructions that such a version existed, created likely in 1940 or even before the war, but as the Bletchley Park history of Hut 8 notes, “forearmed was not forewarned.”2 The four-rotor’s appeal was exactly that—an extra rotor that multiplied the already astounding odds against decryption another twenty-six times, rendering it almost impervious to penetration.3 The cryptographers swiftly embarked on designing a special Bombe that could attack the four-rotor, but estimates put delivery at spring 1943 at the earliest, and even then it relied on pinched material—the essential code books, ciphers and tables—to operate efficiently.
The Kriegsmarine as a whole had no proof of the systematic British penetration of their three-rotor Enigma machines. They had therefore felt no urgency to implement a costly and time-consuming conversion of their entire encryption system. However, with the swing of the pendulum in the war at sea in the summer of 1941, the ever-vigilant Admiral Karl Dönitz, suspecting that his U-boat communications had been compromised, ordered his U-boats in the Atlantic to implement use of the four-rotor machine beginning on February 1, 1942. It was exactly what Godfrey had been dreading, though the British as yet had no knowledge of this specific order. Meanwhile, the Naval Intelligence Division and Bletchley Park were grappling with a two-part question: How long did they have before this new machine would appear, and how pervasive would it be? The nightmare scenario from Godfrey’s perspective would see the device introduced to the entire surface and submarine fleets of the Kriegsmarine, leaving the British, without this crucial and hard-won weapon in the signals intelligence war, entirely in the dark.
After Dönitz discontinued use of the Dolphin key for his U-boats in the Atlantic and introduced the new key, Triton, Turing and the cryptographic team in Hut 8, fearing the worst, struggled frantically with the problem for several days before they realized that the change stemmed from a separate three-rotor key and not the new four-rotor machine. But the scare rocketed up the chain of command to Churchill, who was by now accustomed to his daily delivery of naval Ultra in the “small red box” direct from Stewart Menzies at the Secret Intelligence Service.
Suddenly deprived of U-boat message traffic, Menzies wrote to Churchill immediately to explain what had happened and to assure him that everything was in hand. “From the beginning of October, our difficulties have been increased by the Germans separating the U. Boat cyphers from the Main Fleet traffic,” he told the prime minister. “The latter should present no increased difficulties, but the U. boats present a separate problem which will have to be solved by our machines.” When Menzies reported progress a few days later, Churchill responded with a measured and encouraging note: “Give my compliments to those concerned.”4 With the all-clear a few hours later, Churchill simply replied, “Good.”5
By this time, Bletchley Park had mastered the use of cribs, or cheats, to break into the three-rotor Enigma traffic—an approach Turing hoped would solve the four-rotor challenge should it appear. First, however, his team would require the materials from which to crib. For months the cryptographers relied on the lower-level codes and ciphers to provide what they needed. RHV (short for Reservehandverfahren), for example, was an emergency hand cipher used by vessels as a backup for Enigma when it broke down or on vessels not yet outfitted with the machine. E-bars, B-bars and WW (or Wetterkurzschlüessel), the weather code, were all “short-signal” ciphers (specially formatted, re-enciphered messages) that gave German U-boats and ships a quick way to send brief but standard messages without staying on the air for long and betraying their position to British direction finding, radio finger printing or traffic analysis.6
Other ciphers—such as the Werftschlüssel, a dockyard hand cipher, which touched on the activities of all vessels from the lowliest harbour dredger to U-boats to the Tirpitz (the Bismarck‘s sister ship) operating in port—paid huge dividends because this traffic supplemented and rounded out those messages sent via the Enigma machines. The “lesser” messages might be about damage to ships, building progress, and special orders for radio silence on certain occasions, making these ciphers a crucial band-aid solution during Enigma blackout periods.7 Unfortunately for the cryptanalysts, every so often these codes and ciphers changed too, requiring further pinches. Which is what happened when, at the end of November 1941, the Kriegsmarine introduced the new set of bigram tables.
The great worry for Godfrey and the NID was the double-edged nature of pinches: they helped to solve the problem, but they also piqued German interest in their own security, making it progressively more difficult to maintain that success. The British had no choice but to approach the situation in a more guarded way. In this case, when Combined Operations Headquarters asked Section 1, the geographically organized “country section” in the NID that covered Scandinavia, as well as the Inter-Services Topographical Department for a work-up for a return raid to Norway, Godfrey pounced on the chance to hitch a pinch operation onto this Combined Operations train, now under the command of Lord Louis Mountbatten.
In late October 1941, Churchill had lost patience with Sir Roger Keyes, his Director of Combined Operations, and appointed the youthful captain Lord Louis Mountbatten, a great-grandson of Queen Victoria, to replace him. By this time a growing pessimism had engulfed the indomitable old First World War veteran, who told Mountbatten as he passed the torch that “Britain had lost the will to fight.”8 Keyes was completely frustrated by the lack of co-operation from the land, sea and air service branches. Without any real power, he had been forced to struggle constantly with the chiefs of staff and with Churchill himself to get the precious assets he needed to conduct even pinprick raids along the European coast.
“Dickie” Mountbatten, as he’d been known since childhood, represented the new war. He was bold, vain, diplomatic and highly ambitious, ready to engage w
ith the enemy. Churchill ordered him to take the offensive and develop a programme of commando raids along the Norwegian and Atlantic coastlines that would tie up German resources and help prepare for the Allies’ eventual return to Europe. Before long Churchill promoted him to commodore, and in the spring of 1942 he changed his title from Director of Combined Operations to Chief of Combined Operations (CCO)—the same position Keyes had argued for in vain. That distinction allowed Mountbatten to serve as a member of the Chiefs of Staff Committee, despite palpable resentment from the other service chiefs, who viewed his organization as a bastard stepchild and resented his rapid rise in rank. In due time Churchill promoted him to vice admiral in the Royal Navy, bestowing on him simultaneously the honorary ranks of air marshal in the Royal Air Force and lieutenant general in the army, making him the only individual besides the King to hold rank in all three services. It was an extraordinary rise to power, despite his reckless “palace playboy” image.9
Mountbatten had entered the Royal Navy as a cadet at thirteen, and at forty-one, after a quarter-century of service aboard battleships, submarines and destroyers, he exhibited a flair for signals and the nascent wireless technology they employed.10 By 1941 he was commanding destroyers in combat in the English Channel and the Mediterranean—though with dubious results. Six months before his appointment to Combined Operations, his destroyer HMS Kelly was lost while evacuating British troops from Crete, following a direct hit from Stuka dive-bombers—a scene played out heroically in the film In Which We Serve, starring his friend and rumoured lover, Noël Coward.11 At the time of his appointment he was preparing to take his rising star to the bridge of the aircraft carrier HMS Illustrious. As far as Churchill was concerned, however, Mountbatten was the perfect candidate to handle the new raiding operations he intended to expand in size and scope.
Like Godfrey, Fleming and Churchill, Mountbatten possessed a maverick personality and displayed little fear of doing things in unconventional ways. Later, he would skilfully manoeuvre his way through the treacherous waters of Whitehall by relying on his well-oiled personal “force enhancers”—matinee-idol looks, royal bloodline and innate charm. As Elizabeth Nel, Churchill’s secretary, recalled years later: “His was quite the most glamorous personality among our circles; not only was he tall and extremely good-looking, with gold braid flashing on his uniform, but he seemed to exude a special kind of charm which had us all falling over backwards.”12 Critics claim, however, that much of Mountbatten’s meteoric rise stemmed from a mix of Churchill’s guilt and his notorious penchant for patronage appointments. Churchill had sacked Dickie’s father, Prince Louis of Battenberg, as First Sea Lord at the outbreak of the First World War because of the political optics of his German heritage and name. Now he was ready to make amends and repay the son—with his newly anglicized name, Mountbatten—for his unwavering support during Churchill’s own years in the political wilderness, when his repeated warnings about appeasing Mussolini and Hitler had been met with derision.
In October 1941, Winston Churchill appointed the youthful Lord Louis Mountbatten as Chief of Combined Operations. Despite his “palace playboy” image, the bold, ambitious and glamorous “Dickie” Mountbatten, a great-grandson of Queen Victoria, like Ian Fleming clearly understood the paramount importance of intelligence at the dawning of the information age. Here he is photographed by Yousuf Karsh for the cover of Maclean’s magazine, February 1, 1944. (photo credits 5.1)
What has never been appreciated in the standard biographies of Mountbatten is that this upstart royal possessed something that was vitally important both to Churchill and to Britain’s pressing needs: an understanding of the fundamental nature and significance of intelligence, along with an intimate knowledge of signals intelligence and cryptography that appealed to the prime minister in a primordial way. “I was born and bred in an atmosphere of Naval Intelligence,” Mountbatten wrote. His father, who had served as Assistant Director and then Director of Naval Intelligence at the turn of the century, “continued to talk of the fascination and importance of Intelligence even after he had moved on.”13
Furthermore, like Ian Fleming, Mountbatten exhibited technocratic zeal and embraced modernity. He developed the signals intelligence capabilities for his station while working as a fleet wireless officer in the Mediterranean, where he raised the standard of signalling to new heights. During a brief stint at the signals school in Portsmouth, he earned a reputation for energy, efficiency and inventiveness and was well respected for his cryptographic foresight. He urged the Royal Navy to adopt the Typex encryption machine as the British equivalent of the German Enigma at a time when few of his colleagues had any faith in this device. Later it was readily adopted.14
“I realized I could not expect to achieve any successes without really good Intelligence and a knowledge of how to use it,” Mountbatten wrote after the war, attributing many of his achievements as Combined Operations chief and later as supreme Allied commander in South-East Asia to the fruits of this work.15 His interest in and devotion to naval intelligence, and in particular to signals intelligence, reveals a long-ignored cornerstone of the Mountbatten–Churchill relationship. Despite his daring and aggressive spirit that bordered at times on the reckless, he recognized the need to foster the intellectual and technological work at Bletchley Park—a process and a product that was increasingly viewed as a new-found natural resource.
The injection of a charismatic and influential character like Mountbatten into the intelligence-gathering world reinvigorated the potential the raiding scene offered to the war effort. For Godfrey, Mountbatten’s ascendancy to the crown of Combined Operations not only ensured continued co-operation on pinch matters but amplified the possibilities. The coming twin raids on the Lofoten and Vaagso Islands in the final days of 1941 were proof of that—especially as they turned out to be the most successful pinch raids of all.
Until this point in the war, attacks carried out by Combined Operations had been limited to small hit-and-run raids along the coast or to unopposed landings—as in Lofoten the previous March. The plan to return to the Lofoten area had been on the books since June, when the Ministry of Economic Warfare (MEW), which was responsible for attacking German economic interests, approached the Special Operations Executive (SOE) about conducting a fierce campaign of industrial sabotage throughout Norway. At this point, however, the means for such action was lacking. SOE needed a catalyst, a vehicle and a “coalition of the willing” to put any raid into effect. As things turned out, very few missions or operations were carried out for monocausal reasons. Rather, to attract co-operation from the other services, even in a minor way, targets had to offer something that appealed to them all. Originally, under Sir Roger Keyes’s direction, Combined Operations had shown little interest in spearheading such raids. When Mountbatten took over, however, the pinch needs of Godfrey’s NID meshed well with the evolving strategy of Great Britain’s ever-widening war effort.
After Hitler’s invasion of Stalin’s Soviet Russia on June 22, 1941, the British had entered into a tenuous alliance with their former enemy. Despite his intense hatred of Communism, Churchill had no hesitation in joining forces with the Soviet Union at this time. “If Hitler invaded Hell,” he declared, “I would at least make a favourable reference to the Devil in the House of Commons.”16 Simply put, the British and the Western world in general needed the Soviet Union and its most precious natural resource—manpower—to have any hope of defeating Hitler’s armies. Yet they remained fearful that the Russians might give up more quickly than the Czarist armies had done in the First World War. In an effort to encourage Stalin to fight on, Churchill needed to demonstrate the value of his alliance in any way possible short of opening a second front by invading Western Europe—an impossible proposition at the time.
So Churchill decided to extend the hand of friendship, arranging for British-made weapons and materials vital to the Soviet war machine to reach the Soviet Union via massive Arctic convoys that would skirt German-occupied
Norway and bring the goods to northern Russian ports. In addition, using a series of amphibious raids along the Norwegian coast, he hoped to fix Hitler’s attention on that region. If he could convince the Nazi leader that Norway had become the “zone of destiny” where the war in the west would be won or lost, he would draw German air and land forces away from the Russian front.
A return to Norway would not only satisfy these desires but offer a further opportunity to restock the bare shelves at Bletchley Park. If Mountbatten could deliver the crucial pinched material, he would prove the value of Combined Operations under his command.17 With all these objectives in mind, Churchill and the Chiefs of Staff Committee approved a twin operation—Operation Anklet and Operation Archery—that Combined Operations would carry out close to the Norwegian coast. Together, these two operations could deliver a one-two punch in the Lofoten Islands (Operation Anklet) and on the island of Vaagso, three hundred miles to the south, between Trondheim and Bergen (Operation Archery). The ostensible purpose of Operation Anklet was to seize and hold the harbour at Reine as an advanced naval base from which the British could prevent German interference with the Arctic convoys, but in fact it would allow the SOE and the MEW the chance to wreak havoc on the local fisheries industry and provide a fertile environment to troll for further Enigma-related material.18 A strike at Lofoten would also serve as a diversion to draw German attention away from the main raid—Operation Archery—which was designed specifically to fulfill the intelligence-gathering requirements of the NID. In other words, it would be a pinch raid.
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