People who killed each other – soldiers, sailors, airmen – were the most conspicuous, yet in some ways least interesting, participants in the Second World War. Outcomes were also profoundly influenced by a host of men and women who never fired a shot. All of the belligerents waged an unceasing secret war – a struggle for knowledge of the enemy – to empower their armies, navies and air forces through espionage and codebreaking. General Albert Praun, the Wehrmacht’s last signals chief, wrote afterwards: “All aspects of this modern ‘cold war of the air waves’ were carried on constantly even when the guns were silent.”


I thought I knew quite a bit about the war, but was amazed by some of the tales I encountered while researching my latest book. There was the Japanese spy chief whose exploits caused him to be dubbed by his own men ‘Lawrence of Manchuria’. And there was Karl-Heinz Kramer, a German spy in Stockholm who warned Berlin in September 1944 that the Allies were about to stage a mass parachute drop to seize a bridge over the Rhine. His forecast was ignored, and after the war it was discovered that Kramer’s supposed British informants were figments of his imagination: the Arnhem message was an inspired but wild guess.

Meanwhile, one of the Soviets’ wartime spy chiefs, Pavel Sudoplatov, earned his spurs by presenting a Ukrainian nationalist in Rotterdam with a handsome box of chocolates… which blew the man to pieces minutes later. In the far east, bitter hostility between British and American secret services reached a nadir in January 1945, when USAAF aircraft shot down two RAF Liberators, apparently deliberately, because they were carrying French agents into Indochina against Washington’s wishes.
The Soviet superspy Richard Sorge once said that spying should be done bravely – and that was certainly how he did it. He began his brilliant campaign to penetrate the German embassy in Tokyo in 1933 by befriending the Wehrmacht colonel who soon afterwards became Hitler’s ambassador – and by sleeping with the colonel’s wife. Before Sorge was finally arrested eight years later, and dispatched to the gallows, there was scarcely a handsome woman within his reach whom he had not seduced, nor an embassy secret that had gone unreported to Moscow.
Not the least remarkable agent of the war was a man few people have ever heard of, the Special Operations Executive’s (SOE’s) Ronald Seth, who was parachuted into Estonia to start a resistance movement in October 1942. Seth was next sighted in Paris in 1944, having become a protégé of German intelligence, trained to drop back into Britain. This fabulously weird man’s doings fill a thousand pages in the files of SOE, MI6, MI5, MI9 and Hitler’s Abwehr (military intelligence). It almost defies belief that Seth’s operational codename was ‘Blunderhead’.

In my new book, as in all my books, I have attempted to paint the big picture – in this case, the significance of intelligence to each nation’s war effort – then woven in human stories such as these about spies, codebreakers, guerrillas and intelligence chiefs. The Second World War witnessed an explosion of covert operations such that, in Professor Richard Aldrich’s words, “secret service became the struggle’s growth industry”. Never in history had such vast resources been lavished upon garnering information. The Americans alone spent half a billion dollars a year on sigint – signals intelligence.

Harnessing civilian talent

Most of this was wasted, of course, but today we are in no doubt that the western Allies did intelligence better than their enemies, partly because they gave free rein to superb civilian talent. When the British official history began to be published 30 years ago, I suggested to its author, Harry Hinsley, a veteran of the codebreaking unit at Bletchley Park, that it seemed to show amateurs achieving much more than secret service professionals. Hinsley replied, rather testily: “Of course they did. You wouldn’t want to think, would you, that in peacetime the best brains of our society wasted their lives in intelligence?”

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I’ve always thought this important. Battles could be fought by men of limited gifts, the virtues of the sports field: fitness, grit, skill with weapons. But intelligence services suddenly needed brilliance – and Britain was the place where they got more of it than anywhere else. Most books on this theme focus on single nations. I have tried instead to explore the global story. I’ve written a lot about the Soviets, whose doings are unfamiliar to most western readers, and who created the largest spy networks the world has ever seen, across continental Europe and in Britain and the US.

The ‘Red Orchestra’, upper-middle-class, leftwing Germans, provided Moscow with superb intelligence about Hitler’s war machine between 1935 and 1942. They were led by astonishing personalities: the Luftwaffe officer Harro Schulze-Boysen and his wife Libertas, the intellectual Arvid Harnack and his American wife Mildred, all four of whom eventually met dreadful deaths at Nazi hands.

Spymasters were often unsure which side their agents were really on, and in some cases doubt persists to this day. The British dwell obsessively on the treason of the so-called Cambridge Five. But fewer people notice what we might call the Washington and Berkeley 500 – a small army of American leftists who briefed Soviet intelligence not merely about the atomic bomb but also about every aspect of US policy and technology.

Many books about intelligence focus on what spies and codebreakers found out. The only question that matters, however, is of how far their discoveries changed outcomes. Did they prompt action by commanders in the field and at sea? It is fruitless to study in isolation any nation’s pearls of revelation. These must be seen in the context of thousands of pages of trivia and nonsense that crossed the desks of analysts and warlords.

I am struck by the number of spies whose only achievement abroad was to stay alive, at hefty cost to their employers, while collecting information of which not a smidgen assisted anyone’s war effort. Perhaps one-thousandth of 1 per cent of material from secret sources changed battlefield outcomes. Yet that fraction was of such value that nations begrudged not a life nor a pound, rouble, dollar or Reichsmark expended in securing it.

Until late 1942 the wartime sigint competition was much less lopsided in the Allies’ favour than legend suggests. Hitler had his own Bletchley Parks, and the Germans broke important codes, with consequences for both the battle of the Atlantic and the north African campaign. Admiral Karl Dönitz’s men achieved reasonably regular breaks into convoy communications, though fortunately only about one signal in 10 was broken quickly enough to concentrate U-boats on targets. A secret postwar American study of German naval intelligence concluded: “The enemy possessed at all times a reasonably clear picture of Atlantic convoys with varying degrees of accuracy as to the routes and day-by-day plotting.”

Such failures sometimes had perverse consequences. Dönitz several times became fearful that the British were reading U-boat codes, and ordered inquiries. In the end, however, he allowed himself to be reassured by the vulnerability of the Allies’ convoy traffic. He reasoned that if the Royal Navy was clever enough to read the German hand, its chiefs would have stopped this costly hole in their own communications.

Had the Allies’ conduct in the battle of the Atlantic suggested omniscience, Dönitz would almost certainly have suspected the British breakthroughs in deciphering his encrypted communications, and slammed shut the window on U-boat operations that had been prised open by the brilliant codebreakers of Bletchley Park.

As for the land war, until late 1942 German and Allied sigint were in about the same place. The Afrika Korps thought the British 8th Army’s wireless discipline very slack, and attributed to this some of Rommel’s triumphs. The so-called ‘Desert Fox’ called the Wehrmacht’s 621st Radio Interception Company his ‘circus’, and it was deemed a major disaster when in July 1942 New Zealanders overran and destroyed it. Worse for Rommel, at about the same time, Washington belatedly changed its diplomatic codes. For many months, he had been reading what he gratefully called his ‘little Fellers’ – the dispatches of Colonel Bonner Fellers, the American military attaché in Cairo, who revealed almost every detail about British deployments and intentions.

After Bletchley persuaded the Americans to repair this gaping security breach, the Germans never again secured such a superb source. For the rest of the war they read only lower Allied codes, though spasms of carelessness enabled the Germans to piece together orders of battle, just as the British and Americans did with German communiqués.

The Wehrmacht out-station in Athens, for instance, once read a message from a British paymaster in Palestine, instructing a division moving to Egypt to leave behind its filing cabinets. This enabled a big red pin to be shifted on the map of Montgomery’s deployments. Later, the Germans discovered that the American 82nd Airborne division had been redeployed from Italy to Britain because they broke an administrative message about a paratrooper facing a paternity suit. They also deduced an impending attack in Italy when they decrypted a signal ordering a rum issue for the assault units.

Bletchley’s brilliance

We should acknowledge that German codebreakers achieved important successes – before thanking our forefathers’ lucky stars that they did not, in the end, match the men and women of the Government Code and Cypher School outside a dreary suburban town in Buckinghamshire: Bletchley Park.

Alan Turing was in a class of his own. Yet the Bletchley Park story is far more complicated than such simplistic films as The Imitation Game suggest. First, far from anybody at Bletchley persecuting Turing, his genius was always recognised there. Second, the GCCS’s achievement was a team effort by one of the most remarkable groups of human beings ever assembled – Turing could have achieved nothing without that fellowship.

Legend has it that Bletchley, through Turing’s Bombes – electro-mechanical machines that helped decipher messages encrypted using German Enigma machines – gained open access to the enemy’s communications. This is untrue. The codebreakers didn’t walk on all the water all the time. Though a lot of Luftwaffe and naval traffic was read from 1941 onwards, breaking army Enigma messages was hugely difficult. As late as September 1944, Hut 6 at Bletchley could read only 15 per cent of army messages. Many breaks took days to achieve, and reached battlefield commanders too late to influence events.

Moreover, an increasing number of the Germans’ most secret messages were enciphered not with Enigma, but instead through teleprinters that employed an entirely different system. The achievement of Bletchley’s people in cracking this system was arguably greater than that of breaking Enigma. The most widely used German teleprinter was the Lorenz Schlüsselzusatz (SZ) – codenamed Tunny at Bletchley – which transmitted in a non-Morse language. After British interceptors started to record this incomprehensible stutter, from August 1941 a Bletchley team probed its significance.

Piece by piece they groped towards the solution of the Lorenz riddle, handicapped by the lack of a physical example of the Germans’ transmitter (whereas they had had an Enigma machine). The man who made the initial discoveries is scarcely known to posterity, yet deserves to be almost as famous as Turing.

Bill Tutte was a 24-year-old former chemistry student turned mathematician. The son of a gardener, he won a scholarship to the Cambridge and County Day School, then progressed to Trinity College. In October 1941, Tutte was assigned to study Lorenz, and spent months seeking to divine what kind of machine might generate the noises recorded by the interceptors. By sheer brainpower he eventually established that the teleprinter had two sets of five wheels, with 501 settable pins and a further two motor wheels, between them creating a range of combinations much greater than Enigma’s. A Bletchley chief hailed Tutte’s contribution as “one of the outstanding successes of the war” – and so it was.

Fishing for information

Establishing the machine’s character was a vital beginning, yet the problems of reading its traffic remained huge. By the summer of 1942, the need to crack Lorenz had become desperately urgent. The more the Germans used it for top-secret communications, the less they used Enigma. Between July and October 1942, by extraordinary endeavours that owed little to mechanical assistance, a Bletchley team read some messages. It was learned that one of the teleprinters was named Sägefisch (sawfish), so different German keys used in setting Lorenz were allocated fish codenames at Bletchley – Bream, Grilse, Octopus and so on. Some of the most momentous German messages were encrypted in Jellyfish.

Bletchley reported in August 1943: “The quality of the intelligence derived from the Fish keys is of the highest order.” Decryption attempts became far more successful towards the end of the year, when new technology – first, the ‘Heath Robinson’, then Colossus – was deployed.

Decrypts from both Enigma and Lorenz were known indiscriminately to Allied field commanders as Ultra, and these enabled them to plan operations in the second half of the war with a confidence vouchsafed to no previous warlords in history. But it deserves emphasis that, though Ultra was a marvellous tool, it was not an Excalibur, magicking victories. Reading an enemy’s hand did not diminish its strength.

Until late 1942, again and again the British learned where the Germans intended to strike, but it did not save them from losing the battles that followed. Hard power was always indispensable to the exploitation of secret knowledge.

The British have always been justly proud of their deception successes, but others also played this game, notably the Soviets, sometimes with awesome success. Ian Fleming’s thrillers are said to bear no relationship to the real world of espionage.

Yet, when reading contemporary commissars’ reports and memoirs, I am struck by how uncannily they echo the mad, monstrous, imagined dialogue of such people in From Russia With Love. Some of the plots executed by Stalin’s spymasters were no less fantastic than Fleming’s, and dwarf in scale those of the western Allies.

For instance, in December 1941 a personable young man named Alexander Demyanov, descendant of a great noble family, skied into the German lines south-west of Moscow and announced that he represented a pro-Hitler resistance group committed to restoring the tsars.

The Abwehr embraced him, and a few months later parachuted him back into Russia, codenamed Agent Max. Demyanov soon reported that he had become a wireless operator at Red Army headquarters and, for more than two years thereafter, passed fabulous information to Berlin.

Stalin’s pivotal deception

Colonel Reinhard Gehlen, chief of German intelligence on the eastern front, cherished Max as his star source. Meanwhile, the spy’s dispatches found another fascinated audience – in Britain. Hugh Trevor-Roper, later a controversial Oxford historian, spent the war monitoring the Abwehr for MI6. During my research I decided that the snobbish, rude, arrogant Trevor-Roper was one of the most remarkable British intelligence officers of the war. From 1942 onwards he knew more about Hitler’s secret services than anybody in Germany, because he was privy to the identities of all of the double agents controlled by the Twenty Committee (so named as a nod to that number in Roman numerals: XX – ‘double-cross’) in London.

Courtesy of Bletchley, the donnish officer pored over Agent Max’s early dispatches – and warned the Soviets they had a security leak the size of the Grand Canyon. When they took no notice, Trevor-Roper decided that Max must be a double, controlled by Stalin’s NKVD. In November 1942 came Stalingrad and operation Uranus, the Soviets’ devastatingly successful double-envelopment of the German 6th Army. Around the same time further north, the Red Army also launched another big offensive, Operation Mars – which proved a bloodstained failure.

This caused the British to conclude that Agent Max could not conceivably be working for Moscow – because he had warned the Germans that Mars was coming, enabling them to shift reinforcements northwards to meet it. Nobody, reasoned these rational men serving a western democracy, could have sacrificed 77,000 Soviet lives to promote a deception. But Stalin did just that. The evidence now seems incontrovertible: that Agent Max was indeed the NKVD’s Agent Heine; and that, on the Soviet warlord’s personal authority, the Germans were told of Operation Mars to distract them from Uranus. This was surely one of the most remarkable intelligence stories of the war.

Many things about the 1939–45 era remain disputable, but no informed person doubts that Bletchley was one of the most remarkable institutions the world has ever known, forming a key part of the narrative of Britain’s achievement in the conflict. It remains nonetheless weird, almost beyond imagining, that the Germans never recognised the vulnerability of Enigma and Lorenz. They received endless clues and tips: in my book I tell the story of how, in May 1942, a German commerce raider seized the Australian freighter Nankin, and found aboard top secret Allied reports based on Ultra intercepts, which were eventually forwarded to Berlin. And in 1943 a Swiss intelligence officer, exploiting a warning apparently from an American source, told the Abwehr that the Allies had broken the U-boat codes.

Even then, a most un-Germanic mental laziness prevailed. While the Third Reich executed wholesale Allied spies, traitors and saboteurs, its functionaries remained oblivious of the most deadly of all threats to its security – a few hundred tweedy, bespectacled young academics labouring in drab, suburban Buckinghamshire. The only explanation is hubris: an institutional unwillingness to believe that their British enemies, whom they so often humbled on the battlefield, could be that clever.

Although there are many stories in my book about bungles and failures, in intelligence as in everything else related to conflict, victory is won not by the side that makes no mistakes, but by the one that makes fewer than the enemy. By such a reckoning, the final triumph of the British and Americans was as great in the secret war as it became in the collision between armies, navies and air forces.

We should also acknowledge that, for many agents serving their countries abroad, the experience was irresistibly thrilling, albeit at risk of their lives. An SOE officer posted to the Levant described the impact on local listeners when he used the French word intelligence to describe his mission: “The sharp intake of breath by Arabs who had read their romans policiers, and knew the omnipotence, omniscience and ruthlessness of the British Secret Service, was flatteringly audible. Some instantly asked me if I was a lord.” He loved it. So, too, did most other spies of many nations. Why else would they have taken the work?

Sir Max Hastings is a military historian and journalist.


This article was first published in the November 2015 issue of BBC History Magazine