He strode over to her. “Good. You’re here. Follow me.”
“Sir.”
As a civilian, she was not obliged to show him military deference, but she did so anyway. It helped to keep the nature of their relationship clear, and it was more comfortable for him. She guessed the drill for the morning, because it was the same every morning. First they would go to the main chart table, where the night’s decrypts would already have been whittled down to two or at the most three possibilities. There would be an open discussion, and she would provide her analysis. Next, she and Bermonsey would go to the closed operations office at the other end of the hut, where he would make the final decision. At a pre-appointed time, Bermonsey would pick up the phone and call a secret office in the Naval Intelligence Division of the Admiralty’s Operational Intelligence Center, where the advice from Bletchley would be recast as the commander-in-chief’s orders and sent to the commanding officer, Western Approaches, in Liverpool, or directly to the convoy commodores themselves. Within twenty minutes of Bermonsey picking up the phone, the helmsmen in the ships of the chosen convoy would be changing course. Nobody outside this room would know which other convoys that could have been saved had been sacrificed for the greater good. The steps in the procedure were always the same, like the ritual of a dawn execution, one always with the possibility of a last-minute reprieve.
Fan knew that Bermonsey was in an extraordinary position. As a mere commander, an acting rank at that, he should not have had the authority to issue orders to the highest echelons of the Admiralty. Officially, therefore, his messages to the OIC following these meetings were couched as advice, to be acted on further up the chain if the rear admiral commanding OIC saw fit. Unofficially, his messages were translated into operational orders without exception. Churchill had taken Alan Turing and his team under his wing when he saw that their efforts might be thwarted by those who disliked “boffins,” and had issued a personal directive that the outcome of all that effort was not to be hindered by military red tape. Anyone higher up in the Admiralty who kicked up a fuss was removed, instantly. Fan knew that the judgments made in this room were tantamount to orders from the commander-in-chief himself.
She followed Bermonsey to the chart table. She could see that he was on edge, that his hand was shaking slightly as he opened a file. He was probably running on empty again, fueled by tea and cigarettes. Beside him stood Captain Pullen, a retired officer who had done Bermonsey’s job during the latter stages of the Great War and had been re-employed to be in charge of the day-to-day running of the hut, but without authority over the Ultra output to the Admiralty. Around the table were a dozen others: girls like Fan, several naval officers, and two of Turing’s team who had been shuffled here to make use of them after the main decryption breakthrough, both of them disheveled young men who looked as if they had walked straight out of a Cambridge common room.
The two Americans came and stood in the wings, watching while one of the junior Royal Navy officers arranged some gaming pieces and pencils on the pinned-up chart of the Atlantic in the center of the table. Fan glanced at the shuttered window beside them, seeing that the sun was breaking through. It had been another long, hard winter, the fourth of the war. For the first time she had sensed a cautious optimism while she had been in London over the last few days. The tide had finally turned in the campaign against Rommel in North Africa, and on the Russian front; in Britain, the huge build-up of troops and equipment could only signal imminent invasion plans. And yet for the men actually on the battle lines, that optimism would probably have seemed far-fetched. For those at sea, winter might be over, but the Atlantic was still swept by gales and cold enough to kill a man in minutes. For those men, her men, men who so rarely saw the enemy but who lived in his shadow day and night, the war went on, relentless and unchanging, the dark angel of death ever-present just beneath the waves and over the horizon.
Bermonsey glanced at the wall clock, and then at his watch. “Right. 0630 hours. My phone call to the Admiralty is scheduled for 0715. You have fifteen minutes for your assessment. Lieutenant Hardy?”
The naval officer opposite Fan who had laid the counters on the chart sat down and arranged his papers. He was about her age, a recent arrival from the Operational Intelligence Center, one of two officers at the table whose job was to provide a naval briefing to complement her own more mathematical analysis. He had only been here a few weeks, but had already acquired the distinctive flushed, pallid look of long-term Bletchley inmates, a consequence of too little sunlight and too much time in smoky, overheated rooms. He picked up a ruler and leaned over the table, pointing at the map as he spoke.
“The Ultra intercepts from last night reveal three U-boat patrol lines in the North Atlantic, here, here and here,” he said, tapping the map in three places. “To the south, a line the Germans have code-named Amsel, meaning blackbird, comprising eleven U-boats. To the east, off Greenland, Meise, blue tit, thirty boats, covering the northern route. And finally on the western side of the mid-Atlantic air gap, Specht, woodpecker, seventeen boats, arranged in a line running south of Greenland.”
“No wolf packs?” Bermonsey asked.
Hardy shook his head. “No wolf packs. These are not roving attack formations. They are strung-out, static lines, like fishing gillnets.”
Bermonsey pursed his lips. “And the convoys?”
Hardy moved the pointer from the pencils indicating the U-boat patrol lines to the backgammon pieces he had arranged across the map. “As of 0500 hours, there were some three hundred and fifty merchant ships in the North Atlantic. Most are within the Western Approaches or off the North American seaboard, well within air cover. The two mid-Atlantic convoys that should concern us most are SC-127 and ONS-5. Patrol line Meise was deployed to catch SC-127, but three days ago the convoy slipped through a gap in the line, completely undetected. SC-127 is by far the biggest prize in the North Atlantic at the moment, an eastward-bound convoy carrying US troops and military supplies for the invasion build-up. But we think it’s safe.”
“And the other convoy?”
“ONS-5 is westbound, so the ships are mainly in ballast. German naval intelligence knew it was en route, not from decrypting our messages but from long-range Luftwaffe Condor patrols out of Norway that were shadowing it. Having let SC-127 slip through the net, patrol line Meise was ordered two days ago to reconfigure to catch ONS-5. Yesterday we intercepted a message sent by a U-boat at 1650 hours showing that they had sighted the convoy. We assume that since then the patrol line will have been constricting, tightening the net and making it less likely that this second convoy will slip through. The Germans won’t want to make the same mistake twice.”
Fan peered at the young officer. Another secret, another fold in the veils that fortified Bletchley, something that even those around this table were forbidden to voice, was that Turing’s team had known for some time that their German equivalent, B-Dienst, had broken the British naval cypher used for Allied North Atlantic convoy messages. As a result, not only was Bletchley playing a game of cat-and-mouse with the Enigma decrypts, pushing and prodding to see how much they could get away with, but they were also playing a similar game in the other direction, keeping the compromised British naval cypher open and using it to feed disinformation to the Germans. They had pushed their luck to the point where B-Dienst would be bound to rumble them soon, so a new naval cypher was ready to be activated. But meanwhile the game with B-Dienst went on, seeing how far they could go in acting on their knowledge without exciting the suspicion of their counterparts in German naval intelligence somewhere deep in their own secret operational headquarters outside Berlin.