One Day in August

by David O'Keefe

  With their ability to dictate when and where they would launch these raids, the NID had the luxury of constructing its public relations lines well in advance of any operation—a crucial element not only in striking a blow in the propaganda war but also in covering each pinch. With the ability to “spin” events in their official communiqués following a victory, defeat or any other outcome, Godfrey, Fleming and their cohorts provided carefully crafted versions of events which satisfied the contemporary press and permeated postwar historical accounts as well, ensuring that the documents classified as Ultra Secret remained just that, even decades after the guns fell silent. In the case of Lofoten, the communiqués, reported almost verbatim, featured the military and other intelligence objectives, except for anything to do with the pinch. By offering explicit confirmation of the sinking of all the enemy ships the raiders encountered, they allayed, or at least reduced, German suspicions of the capture and compromise of their precious communications gear.33

  Although the planners drew many genuine conclusions from the Lofoten operation of March 1941, the main lesson was something that remained hidden to the public for seventy years. Emerging in the aftermath of Claymore was a nascent brand of special operations warfare—a template for properly organized pinch raids that whetted the appetites of both the Naval Intelligence Division and the Naval Section at Bletchley Park for a repeat performance. A series of operations materialized starting in May, just a few weeks before the Bismarck made her fateful breakout into the North Atlantic.

  As in the Lofoten raid, trawlers and minor ships became the focus of the next pinch operation, for several reasons. First, from what he could deduce from traffic analysis, the gifted Harry Hinsley noted that the small vessels, particularly weather-reporting ships, did use a series of codes and, at times, the Enigma machine. The odds were therefore extremely high that these lightly armed and thoroughly vulnerable ships could deliver the materials that the experts at Bletchley Park required; moreover, they would be easier to raid. Second, the weather-reporting ships operated alone and in isolated areas of the ocean, far from prying eyes on shore or above—a decided advantage compared with the Lofoten Islands and other harbours where small ships worked as part of a group of vessels or a flotilla.

  Because these seemingly insignificant vessels did not present an obvious target, capturing them, at least initially, ran a distinctly lower risk of raising suspicion in Admiral Dönitz’s headquarters than an intentional, or even unintentional, capture of one of his U-boats. In an impressive piece of signals intelligence sleuthing drawn from inferences in wireless transmissions and the material captured from the Krebs, Hinsley put together a detailed “hit list” of target weather ships, providing both their potential hauls and their suspected operational locations.34

  The oddly named Operation EB went into effect on May 7, with unprecedented support. To effect the pinch, the Admiralty allocated three cruisers (HMS Edinburgh, Manchester and Birmingham) and four destroyers (HMS Somali, Eskimo, Bedouin and Nestor) from Admiral John Tovey’s Home Fleet, putting them on hold and ready to move at a week’s notice. The scale of this preparation testifies to the utmost importance of the raid, given that these precious assets, particularly the destroyers, were in high demand for anti-submarine patrols with the U-boat war at its most intense. In addition, with Godfrey’s formalization of the pipeline between his NID and Bletchley’s Naval Section, Captain Jasper Haines, RN, became the first liaison officer to work at Bletchley Park specifically for pinch purposes. A striking figure with movie-star looks and silver hair, Haines stood out in the bleak surroundings of the huts and attracted attention from the many young women who worked there. His job was to cull information about specific needs and then go into action with the pinch forces to retrieve what was required and escort it back to London—a risky proposition should he be captured, given his intimate knowledge of Bletchley Park and the cryptographic effort.

  This remarkable photograph shows a “pinch by chance” raid in progress (from later in the war, March 1944). The crew of HMCS Chilliwack are about to board after subduing the German U-boat U-744. They retrieved valuable code books and intelligence documents, though on this occasion much of the material was lost at sea in the raid. (photo credits 4.5)

  Before Operation EB began, Haines briefed the force commanders (cruiser squadron commander Vice Admiral Lancelot Holland and his destroyer captains) on the requirements of the mission—clear proof of the significance of the pinch and the increasing power and influence of Naval Intelligence in such matters. Holland, who would soon lose his life during the battle with the Bismarck, listened intently while Haines explained that he would accompany the raiding force and personally deliver any pinched material directly back to London. He emphasized that “drastic action was important on first sighting to induce the enemy to abandon ship in a panic and … fail to destroy as much as they otherwise might.”35 Although the cruisers had float planes for reconnaissance, Haines had them grounded. He knew that the sight of a search plane would give away the presence of the strike force and lead the crew to dispose of the invaluable signals material. Surprise, followed by what we would now call “shock and awe,” proved the keys to success.

  By 1500 hours on Wednesday, May 7, the ships were on station just inside the Arctic Circle, actively searching for the German weather-reporting ship München. At 1707 they sighted the tiny trawler between the Edinburgh and the Somali. The Somali quickly opened fire at long distance to frighten the crew and then proceeded towards the trawler, along with the Edinburgh carrying Haines on board, at a full thirty knots in “sledgehammer” fashion. The approach partially worked, but the crew still managed to dispose of the Enigma machine and most of its signals material and to fire off a message to their headquarters that they were under attack. By the time Haines arrived on the stricken vessel, the boarding party had seized and bagged what remained of the code and cipher material and had brought the surviving crew on board as prisoners. Later, in the privacy of a wardroom on the Edinburgh, he found “interesting documents … in the spoil”—the Enigma keys for June and the short-signals book (for messages of fewer than twenty-two characters) used by submarines, weather ships and other small vessels in certain circumstances.36 Immediately he photographed the material and, once he returned to Scapa Flow, had the originals flown straight to Godfrey at the Admiralty, who then sent them on to Birch at Bletchley Park.

  An Enigma machine with German code books, setting sheets and other highly prized material sought by British Naval Intelligence for use by the cryptanalysts at Bletchley. These are mock-ups created for the documentary Dieppe Uncovered, based on this book’s research. (photo credits 4.6)

  A rare photograph from the Bundesarchiv of a German “signaller” at work in a wireless room, identified as March 1941. An Enigma machine lies in its box beside him, the three rotors visible at the top of the machine close to his left hand. In U-boats the wireless room was the communications nerve centre, and in the event of a pinch raid the crews were trained to rapidly destroy the machine and the code books. (photo credits 4.7)

  To cover the pinch, particularly as the München had got off a signal before she was boarded, Haines sent a Hush Most Secret message to the Admiralty about his imminent return with an “important” document. He suggested that a press announcement be released mentioning that the München, now in tow, had actually been scuttled by her crew and not captured. Promptly, the story appeared, reporting in great detail the sinking of the ship and, to alleviate German suspicion, portraying the action as strictly incidental. The Kriegsmarine seems not to have suspected any compromise of their cipher material, and the München remained hidden in Scapa Flow until the end of the war.37 Before Haines reached British shores, however, another pinch, this one a classic “pinch by chance,” occurred in the North Atlantic—and it propelled the code-breakers’ penetration of the German naval Enigma to unprecedented levels.

  For more than a year, not one scrap of paper bearing on the Enigma problem ha
d fallen into British hands, yet within days of the seizure of the München, the British destroyers HMS Bulldog and HMS Broadway, along with the corvette HMS Aubretia, captured submarine U-110 after it engaged a convoy off Iceland on May 9.38 The U-boat, commanded by Captain-Lieutenant Fritz-Julius Lemp, the ace who had sunk the Athenia in the opening hours of the war, gave up what Bletchley Park would come to consider the “richest prize” so far. After three days of almost constant depth-charge attacks, Lemp ordered the submarine to surface and its crew to abandon ship.

  Fearing that the Germans had set scuttling charges on a timed fuse and racing against time to reach the submarine before it exploded, a boarding party led by Sub-Lieutenant David Balme from Bulldog paddled quickly in a launch under the watchful eye of cameras that caught the extraordinary events as they unfolded. Once on board, Balme entered the vessel through its conning tower and slipped into its control room, “abandoned in great haste,” he recalled, “as books and gear were strewn about the place.” The signals room, in contrast to the rest of the ship, was in “perfect condition,” with no signs of destruction. Here he found signals books, logbooks and correspondence—and, sitting on the desk, the Enigma machine, still plugged in, as though it had been in use when abandoned. Quickly, Balme organized a human chain and took every book, chart and scrap of paper, along with the Enigma machine, from the vessel, moving it one armful at a time up the conning-tower ladder to the waiting launch. Only when the whole dangerous job was completed did Balme return triumphantly to Bulldog, where he reported the find while the destroyer took U-110 in tow as a cherished prize.39

  To cover the capture and pinch, Godfrey decided to sink the damaged sub en route to the Scapa Flow and the NID swiftly issued a Hush Most Secret message instructing the crew to maintain utmost secrecy and to refer to the U-110 and its capture only by the code name “Primrose.” From that moment forward, Lemp’s submarine ceased to exist, stored away out of sight for the remainder of the war. The British, who were now increasingly co-operating with the still-neutral Americans, did not even inform them of this capture until January of the next year.

  When Bulldog arrived in England, a Naval Intelligence officer, likely Jasper Haines, met the ship and whisked the pinched machine and documents to the Naval Section at Bletchley Park. The materials stolen from the München and the U-110 only days apart provided the answer to Bletchley’s prayers. As a result, the cryptologists could now read naval Enigma messages on the Dolphin key in real time for the month of June and, even more critical, they possessed a copy of the special Offizier codebook—a key to the most secret information circulated to U-boat commanders, such as notifications of upcoming changes in key and encryption systems.

  The overwhelming joy unleashed in the Naval Section by the twin pinches and the sinking of the Bismarck proved short-lived: on June 15, the Germans changed the bigram tables. Foreseen as a distinct possibility, this development prompted the Naval Intelligence Division to launch a repetition of the München pinch.40 Again Harry Hinsley’s trawlers played a starring role, with the Lauenburg, one of ten weather trawlers that ploughed the Atlantic in support of the Bismarck, the intended victim. In an almost carbon-copy replay of the earlier pinch, a task force of two cruisers and three destroyers was specifically laid on for this operation, briefed by Lieutenant Commander Allon Bacon, who worked with Fleming in Section 17. As handsome as Captain Jasper Haines, the thirty-eight-year-old Bacon, “rangy, dark-haired, round-faced,” who before the war had worked in London’s financial sector and for the Foreign Office on signals intelligence assignments, had been recruited into the NID for his intellect and resourcefulness, both of which would be called upon in the upcoming operation.41

  Once aboard HMS Jupiter for the mission, Bacon inspected his boarding party, outfitted like privateers of old with cutlasses and axes, along with their modern submachine guns. The intermittent fog and rain presented perfect conditions, cloaking the progress of the raiding force towards the trawler and maximizing the chance of surprise. After a series of icebergs set off false alarms, the crew finally spotted their quarry in the distance.42

  Jupiter immediately increased to flank speed and headed straight for the trawler. It opened fire with the main armament, intending to frighten rather than kill the crew.43 The men quickly abandoned ship without destroying their communications material; the boarding party entered and grabbed what they were looking for, then sank the vessel to cover their tracks.44 Once again the press played a role in covering the pinch, with a banner headline reading DEPRESSION OFF ICELAND FOR 22 GERMANS. The news report stated that in the course of a “periodical sweep” to the north of Iceland, “our forces sank a German weather reporting trawler, capturing her crew of 22.”45

  This pinch allowed the cryptologists at Bletchley Park to continue to read the naval Enigma traffic after the expiration of the key sheets captured for June and July. In terms of breaking the three-rotor Enigma code, the pinches provided Alan Turing with the “cheats” necessary to mine for the current operational gold and with “cribs” for the increasing number of Bombes being used in the Naval Section’s investigations. As the year went on, the experts employed anything that might give Bletchley a break, even through the back door, into Enigma: weather codes, short-signal codes, the restricted Offizier and Stab ciphers, the German dockyard cipher, a special emergency hand cipher called RHV, and Long-E bars. In fact, the cumulative success of the pinches provided the basis for an almost daily penetration of the Dolphin key for the remainder of the war.

  Frank Birch considered the Lauenburg pinch the “masterpiece of cooperation between Naval Section and the Navy.”46 Along with the other operations, it showed just how far the Naval Intelligence Division had progressed in the twelve months since Operation Ruthless—and how integral these operations had become in both the cryptographic war and the war at sea.

  The sudden change in British fortune against the deadly U-boats in the summer and fall of 1941 did not go unnoticed in higher quarters. In September, Winston Churchill paid his only visit to Bletchley Park, to survey the inner workings of the “intelligence factory” that provided his golden eggs. He was already thoroughly addicted to Bletchley’s end products. Ultra was unique and offered him a direct line to something that nobody else had: a finger on the pulse of the enemy war effort. It was an intoxicating power that the micromanager in him could not resist.

  As First Lord of the Admiralty, he had enjoyed access on demand to all the naval Ultra. “Shortly before he became Prime Minister,” Godfrey remembered, “I had some piece of information to impart and was asked by his private office to go to Mr. Churchill’s bedroom in Admiralty House. He was sitting up, freshly shaved, in an enormous double bed smoking a cigar and surrounded by his morning’s correspondence, despatch boxes, papers, breakfast, a bottle of white wine, coffee, cigars.”47 By the time he became prime minister and the highest authority in the land, he received a daily delivery of all forms of Ultra (not just naval) direct from the head of the Secret Intelligence Service, Stewart Menzies—the man called “C”—who was responsible for the overall production of this rare commodity. Each morning a locked red security box, marked “Only to be opened by the Prime Minister,” would arrive containing the Ultra that kept Churchill thoroughly engrossed for hours on end. It is not surprising, then, that on his congratulatory visit to Bletchley Park, when he was confronted by demands for additional funding for the projects there, he responded with a “prayer” stamped Action This Day. It ordered full and unending financial support for Bletchley and its parent organization, the Government Code and Cypher School (GC&CS).48

  In stark contrast to Churchill, Admiral Dönitz had no idea of the scope of the British cryptographic effort. Although he recognized that something along those lines did exist, he had no clue just how much current success Bletchley was enjoying. After the sinking of the Bismarck, when the majority of her support ships methodically and quickly fell to British action, Dönitz and his staff became suspicious that Enigma had be
en compromised. Then, in late August, the U-boats suddenly lost their ability to find convoys, which were now routinely rerouted because of the steady flow of Special Intelligence the Operational Intelligence Centre was receiving. Dönitz had always doubted the impenetrability of Enigma, and he now decided to introduce a separate key, apart from Dolphin, for his U-boats. Triton, as he called it—the British named it Shark—came into effect on October 3, 1941.

  Because Triton remained a key for a three-rotor machine, it did not create much anxiety at Bletchley after an initial delay. Compounding Dönitz’s worry, one of his submarines, the U-570, simply disappeared after sending a message that she was under attack by British planes and vessels. On that occasion, when the boarding party entered the submarine, which had been badly damaged from depth-charge attacks and prepared for scuttling by its crew, they found a few Enigma-related items: the remains of a destroyed code book and table, and the lid of the smashed machine. The disappearance of the submarine led Dönitz to suspect the worst, and he demanded an inquiry.

  Dönitz’s security advisers assured him that, even if the British had managed to break into the cipher, their success would only be temporary: the odds against permanently subverting the machine were astronomical. However, now that they had the ability to penetrate naval Enigma, the British tended to push their luck to the limit, reaffirming Dönitz’s suspicions. Although they took strict precautions to limit the distribution of Special Intelligence to a tiny circle of “indoctrinated” officers and ensured that reconnaissance, or some other plausible intelligence source, covered operations spawned by the captured intelligence, there was always a chance that, given the frequency at which they were now enjoying success, something unforeseen could occur. The overwhelming power of this source of information tended to blind British intelligence planners to the fact that overuse or misuse might give the game away. In three separate episodes, evidence emerged that led Dönitz to conclude that the three-rotor Enigma used by his U-boats had sprung a leak.