Enigma

Victorian railway town about fifty miles west of Cambridge. Atwood, who liked to cut a dash, insisted on driving with the roof off, and as they rattled down the narrow streets Jericho had an impression of smoke and soot, of little, ugly terraced houses and the tall, black chimneys of brick kilns. They passed under a railway bridge, along a lane, and were waved through a pair of high gates by armed sentries. To their right, a lawn sloped down to a lake fringed by large trees. To their left was a mansion—a long, low, late-Victorian monstrosity of red brick and sand-coloured stone that reminded Jericho of the veterans' hospital his father had died in. He looked around, half expecting to see wimpled nurses wheeling broken men in Bath chairs.
    'Isn't it perfectly hideous?' squeaked Atwood with delight. 'Built by a Jew. A stockbroker. A friend of Lloyd George.' His voice rose with each statement, suggesting an ascending scale of social horror. He parked abruptly at a crazy angle, with a spurt of gravel, narrowly missing a sapper unrolling a large drum of electrical cable.
    Inside, in a panelled drawing room overlooking the lake, sixteen men stood around drinking coffee. Jericho was surprised at how many he recognised. They glanced at one another, embarrassed and amused. So, their faces said, they got you too. Atwood moved serenely among them, shaking hands and making sharp remarks they all felt obliged to smile at.
    'It's not fighting the Germans I object to. It's going to war on behalf of these beastly Poles.' He turned to a handsome, intense-looking young man with a broad, high forehead and thick hair. 'And what's your name?'
    'Pukowski,' said the young man, in perfect English. 'I'm a beastly Pole.'
    Turing caught Jericho's eye and winked.
    In the afternoon the cryptanalysts were split into teams. Turing was assigned to work with Pukowski, redesigning the 'bombe', the giant decryptor which the great Marian Rejewski of the Polish Cipher Bureau had built in 1938 to attack Enigma. Jericho was sent to the stable block behind the mansion to analyse encrypted German radio traffic.
    How odd they were, those first nine months of the war, how unreal, how—it seemed absurd to say it now—peaceful. They cycled in each day from their digs in various country pubs and guesthouses around the town. They lunched and dined together in the mansion. In the evenings they played chess and strolled through the grounds before cycling home to bed. There was even a Victorian maze of yew hedges to get lost in. Every ten days or so, someone new would join the party—a classicist, a mathematician, a museum curator, a dealer in rare books—each recruited because he was a friend of someone already resident in Bletchley.
    A dry and smoky autumn of gold's and browns, the rooks whirling in the sky like cinders, gave way to a winter off a Christmas card. The lake froze. The elms drooped under the weight of snow. A robin pecked at breadcrumbs outside the stable window.
    Jericho's work was pleasantly academic. Three or four times a day, a motorcycle dispatch-rider would clatter into the courtyard at the back of the big house bearing a pouch of intercepted German cryptograms. Jericho sorted them by frequency and call sign and marked them up on charts in coloured crayons—red for the Luftwaffe, green for the German Army—until gradually, from the unintelligible babble, shapes emerged. Stations in a radio net allowed to talk freely to one another made, when plotted on the stable wall, a crisscross pattern within a circle. Nets in which the only line of communication was two-way, between a headquarters and its out-stations, resembled stars. Circle-nets and star-nets. Kreis und Stern.
    This idyll lasted eight months, until the German offensive in May 1940. Up to then, there had been scarcely enough material for the cryptanalysts to make a serious attack on Enigma. But as the Wehrmacht swept through Holland, Belgium, France, the babble of wireless traffic became a roar. From three or four motorcycle pouches of material, the volume increased to thirty or forty; to a hundred; to two hundred.
    It was late one morning about a week after this had started that Jericho felt a touch on his elbow and turned to find Turing, smiling.
    'There's someone I want you to meet, Tom.'
    'I'm rather busy at present, Alan, to be honest.'
    'Her name's Agnes. I really think you ought to see her.'
    Jericho almost argued. A year later he would have argued, but at that time he was