How Britain’s German-born Jewish ‘secret listeners’ helped win World War II
A new book by historian Helen Fry details the daring operation in which the UK eavesdropped on Nazi prisoners, gleaning precious intel — and early graphic accounts of Holocaust
LONDON — It was certainly not what the captured Nazi generals expected — or deserved. As historian Helen Fry describes in her new book, “The Walls Have Ears: The Greatest Intelligence Operation of World War II,” Trent Park, the stately country house in north London to which the prisoners were confined, rather resembled a gentleman’s club.
The most senior generals had their own rooms, with adjoining sitting rooms. There was a room for playing billiards, table-tennis and cards. And, after afternoon tea on Christmas Eve, a festive dinner was laid out for them.
There was even an appropriately deferential welcome for the Third Reich’s top military brass — on arrival, the illustrious POWs were met by Lord Aberfeldy, a distinguished Scottish aristocrat and second cousin of the King.
Aberfeldy told the generals he was their welfare officer and lavished attention upon them. He made fortnightly trips to the capital to buy them shaving cream, chocolate and cigarettes. He arranged for a Savile Row tailor to measure them up for new clothes. He even showed them pictures of his Scottish castle and let slip his own admiration for the Fuhrer.
Nor were the Germans strictly confined to this luxury prisoner of war camp. Senior British officers occasionally took them to dine at Simpsons on the Stand and the Ritz, and invited them to tea at their homes.
As one of the seemingly lucky captives, Lieutenant colonel Kurt Kohncke, suggested: “Our involuntary hosts are thoroughly gentlemanlike.”
But nothing was, in fact, as it seemed. “Lord Aberfeldy” was the creation of British intelligence; no such title existed, and the role was instead played to perfection by one of its officers, Ian Munro.

Thus, writes Fry, behind the façade of the gentleman’s club at Trent Park, the British had constructed an elaborate, highly efficient and, in terms of the war effort, vital espionage operation. Unbeknownst to, and unsuspected by, the Nazi military commanders, Trent Park was wired for sound.
“The generals did not realize that everything that could be bugged was — from the light fittings to the fireplaces, plant pots, behind the skirting boards, under floorboards of the bedrooms, and even the trees in the garden,” Fry says. Even the billiard table had a bugging device in it. The house and its surrounding estate were, Fry continues, nothing less than “a theatrical stage set.”
Unseen by the generals, an army of “secret listeners” — many of them Jewish refugees proficient in the multitude of German dialects being spoken — eavesdropped on their conversations, which were transmitted back to a basement room, the “M” — or miked — room. The conversations were then transcribed, translated, and painstaking double-checked before being passed to onsite interrogators and fired off across Whitehall to key intelligence agencies and government departments.
Fry’s book draws on thousands of files, transcripts and reports in Britain’s National Archives which were quietly released in the late 1990s.

Trent Park was, moreover, just one part of the operation. At Latimer House and Wilton Park, two estates in the countryside of Buckinghamshire, to the northwest of London, similar facilities were established in the early years of the war. While Trent Park’s “special quarters” would, by the time of the Allied victory, house nearly 100 senior German officers, in all, some 10,000 lower-ranked prisoners passed through the three bugging sites during the course of the war.
The eavesdropping would elicit a wealth of intelligence: on the Germans’ battle plans, new technology being developed by the Nazis on U-boats and aircraft, and the progress of Hitler’s secret weapons program that produced the V1 and V2 rockets.
It would lay stark the divisions between pro- and anti-Nazi officers and their reactions to the “July plot” to assassinate Hitler and their country’s impending defeat.
And, most disturbingly of all, there were graphic eyewitness accounts of the mass murder of Jews in the East — on occasion, by the very men who had perpetrated them.

Unlike the generals, many of the more junior POWs would spend only a few days in the facilities while their conversations were listened to and any useful intelligence gleaned. As they expected they would be, they were subjected to interrogations. However, says Fry, these were sometimes “phony, designed to make the prisoners think the British did not know very much or were stupid.”
As Fritz Lustig, one of the Jewish “secret listeners,” later recalled: “Their reaction to interrogation was often particularly fruitful. They would tell their cellmate what they had been asked about, what they had managed to conceal from the interrogator and how much we [the British] already knew.” Only very rarely did prisoners suspect anything fishy.
Enter Colonel Kendrick, the ‘Oskar Schindler of Vienna’
In the first months of the war, German prisoners — sailors rescued from U-boats which had been sunk, and the first Luftwaffe pilots to be shot down over England — were held at the Tower of London. The cells in the historic castle in which the POWs were held had been bugged some months earlier in anticipation of the coming conflict. The Tower saw only limited use — it could accommodate a mere 120 prisoners — and by the new year Trent Park was up and running.
Once the home of Sir Philip Sassoon, a wealthy Iraqi Jew, Trent Park was equipped with listening devices which utilized the latest technology rushed across the Atlantic by the Radio Corporation of America.

Overseeing the whole operation, which had the deliberately bland-sounding title of the Combined Services Detailed Interrogation Center, was Colonel Thomas Kendrick. “His eventful career,” says Fry, “was veiled in total secrecy and would not have appeared out of place in the gritty world of a John le Carré novel.”
A veteran intelligence officer, in the interwar years Kendrick ran the UK’s spy networks in central Europe. His MI6 cover was a posting to Vienna as a British passport officer. In that role, he played a critical part in helping to rescue Jews and the Nazis’ political opponents from Austria after the Anschluss. According to British Foreign Office records, Kendrick and his overworked staff saved around 200 Jews a day, handing out visas.
Fry labels Kendrick the “Oskar Schindler of Vienna,” noting that he “forged documents to enable the country’s Jews to emigrate, even if they did not qualify, and stamped and approved their papers, including applications that were not complete.”
Kendrick even ended up striking a deal with Adolf Eichmann, who had been sent to Austria to clear the Reich’s newest addition of Jews. Under its terms, 1,000 Jews were given illegal visas to enter Palestine. Kendrick was later reprimanded by the Foreign Office for his actions, which had been carried out behind the back of the British government.
Less than six months after German troops entered Vienna, Kendrick was arrested by the Gestapo after being betrayed by a double agent. Interrogated for four days, he was expelled from the Austria for spying.

Back in London, and with a conflict with Germany now thought to be inevitable, Kendrick was charged with putting together the operation which would seek to spy on the prisoners of war who would fall into Britain’s hands.
Kendrick’s methods soon paid rich dividends. As the war progressed and the number of airmen and sailors captured by the UK increased, crucial intelligence was gleaned. The secret listeners learned about potential landing places for Hitler’s planned invasion of Britain. They picked up information, too, about resistance activity in occupied France, Holland and Norway; air raids on the UK; and the impact of the RAF’s bombing of Germany. During the Battle of the Atlantic, eavesdroppers discovered intelligence on U-boat movements and tactics, and even where new highly disguised U-boat pens were being built on the French coast.
Kendrick’s operation also played a part in the so-called “Battle of the Beams,” when Luftwaffe bombers used increasingly accurate radio navigation systems as they bombed the UK at night and Britain scrambled to develop countermeasures. Similarly, prisoners also let slip vital intelligence about the new magnetically-fused torpedoes which could be fired from U-boats. Again, this enabled measures to be taken to help diffuse the threat to British ships.

Vague chatter among the prisoners about Hitler’s “secret weapon” was picked up when the war was barely two months old. Over three years later, talk among the generals helped the Allies to grasp the real purpose of the secret Peenemünde site on the north German Baltic coast, where a deadly new rocket program was underway. The ensuing bombing raids on the site, says Fry, delayed rocket test launches by up to six months. Crucially, it meant the first V1 rocket did not land on London until the week after D-Day. Kendrick’s operation would continue to provide information throughout the war on V1 and V2 mobile launch sites in France and Holland, which were also then be bombed.
German-born Jewish spies take on the Nazis
The intelligence gathered from Trent Park was considered so valuable that when expansion to Latimer House and Wilton was discussed in 1941, intelligence chiefs deemed that it should go ahead “by the earliest possible date irrespective of cost.”
But by 1943 Kendrick had encountered a problem that could not be solved by money alone. The number of POWs had risen with British victories in North Africa — which brought with them the first significant number of army prisoners, as well as generals and commanders — and the workload increased. It would rise again sharply after D-Day. The eavesdroppers also began to find the highly technical language, and German dialects, difficult to comprehend. Up until then, the sites had only employed British-born listeners who were fluent in German.

Kendrick thus needed native German speakers. In the British army’s Pioneer Corps, in which large numbers of German refugees, many of them Jewish, were serving, he found his answer.
Around 100 emigres, many of whom had been temporarily interned by the UK government as “enemy aliens” when the war broke out, were eventually recruited. They were delighted with the opportunity to take part in a highly secretive part of the war effort, having previously been consigned to unskilled labor in the Pioneer Corps. (In the early stages of the war, it was the only British military unit in which the nationals of countries with which the UK was at war could serve.)
As Fry writes, Fritz Lustig, who had fled Germany after Kristallnacht, was typical of Kendrick’s new “secret listeners.” He had been held as an enemy alien on the Isle of Man during the summer of 1940 before being released and joining the Pioneer Corps. After passing a series of interviews in 1943 — and being instantly promoted from a private to sergeant — Lustig found himself working for Kendrick. “Your work here is as important as firing a gun in action,” his new boss told him.
Lustig himself felt no qualms about spying on German prisoners. “They were no longer our compatriots,” he later said. Others expressed similar feelings. “I never felt I was betraying Germany,” said one. “Germany betrayed me.”

The bond between Kendrick and the “secret listeners” was a strong one. He had actually helped the family of one of them, George Pulay, to escape from Vienna. Another of Kendrick’s Jewish team, Ernst Lederer, is believed by Fry to have done more than just listen. Originally from the Sudetenland, he was also used as a stool pigeon. Dressed in a German officer’s uniform, Lederer was one of nearly 50 men — many of them also refugees — who posed as prisoners and helped loosen the captives’ tongues.
Female Jewish refugees, such as Gerda Engel and Susan Cohn, were also employed by Kendrick to help with translation, sorting through intelligence, and clerical work. Occasionally, romance blossomed. One month after the end of the war, Lustig and Cohn were married.
Kendrick and his “secret listeners” were able to learn about the fraught and angry conversations between pro-Nazi generals and the anti-Nazis, whom the former viewed as defeatists. They overheard the aghast reactions to Hitler’s bloody revenge on those who had plotted to assassinate him in Operation Valkyrie in July 1944. And they listened in as the generals showed no emotion on hearing the news of the Fuhrer’s suicide, and, to the horror of their orderlies, clinked glasses of wine on VE Day.
But some of what the “secret listeners” heard was utterly harrowing, especially for those Jews who had families still trapped in Europe. Some, such as Peter Ganz, would indeed discover after the war that members of their family had perished in the Holocaust.
A window into the Holocaust’s full horror
Although some intelligence had been picked up before, most of the detailed information about war crimes was gathered from 1943 onward.

Eavesdropped conversations began to pick up the scale of the horror. One prisoner referred to 300,000 civilians being shot, another talked about the 80,000 Jews being murdered in Lublin, and a third about 5,000 killed in one day in a Ukranian village, all providing graphic details of Einsatz-Kommando massacres. Names that would become infamous — Auschwitz, Mauthausen and Bergen-Belsen — were mentioned; so too were mobile gas trucks, the liquidation of the Warsaw Ghetto, and the murder of “mental defectives.”
Perhaps most shocking of all was the attitude of the prisoners to the Nazis’ crimes that the bugging revealed.
Some, it is true, appeared to recognize the nature of the terror their country had inflicted upon European Jewry. A young sailor relayed an eyewitness account of a massacre in Lithuania, with the words “believe me, if you had seen it, it would have made you shudder.” A pilot recalled chancing with some friends upon the scene of a mass shooting near Lviv. “We shall have to pay for that,” he grimly suggested.

Among themselves, some of the generals, too, seemed to show a similar understanding. “The most bestial thing I ever saw,” said one after witnessing the aftermath of killings in Russia. As Kendrick forced the generals to view photographs and film footage of the liberated camps at Bergen-Belsen, Buchenwald and Dachau, one commented to another: “We are disgraced for all time and not 1,000 years will wipe out what we’ve done.”
But the bugging also picked up far less contrite feelings. Some generals wondered if the photographs were faked. Others suggested that the suffering of Germans at the hands of the Russians was far worse. One general even argued to another that there was too great a focus on the Jews. “Many more Germans died in this war than Jews died in gas chambers,” he said. Another believed that the blame for what had befallen them rested solely with the Jews — “the pest of the East” — themselves. There was also speculation that the British and Americans were set on destroying the German military and academic classes.
Of course, there were also attempts to minimize the culpability of the German armed forces, with a general arguing that “only a few beasts of the SS” were to blame.
But as the generals knew, this was simply untrue. “The unguarded conversations of the generals revealed to the intelligence services that Germany’s military commanders not only knew about the war crimes committed, but some were complicit in it,” writes Fry.
Dietrich von Choltitz, who had served in the East before later becoming the last German commander of Nazi-occupied Paris, for instance, suggested to a colleague: “The worst job I ever carried out — which, however, I carried out with great consistency — was the liquidation of the Jews. I carried out this order down to the very last detail.” Tellingly, von Choltitz was rehearsing the line which many others would also parrot: that they were simply obeying orders.
Kendrick was determined that his operation might help bring to justice those guilty of war crimes. From the outset, he had ordered the secret listeners to preserve any relevant recordings, marking the acetate discs with a large red ‘A’ for atrocity.

However, the transcripts ended up not being used at Nuremburg after British intelligence chiefs decided that they could not publicly expose their eavesdropping methods. Indeed, the M Room files were not finally declassified until the late 1990s after the end of the Cold War.
The veil of secrecy in which the work of Kendrick and his Jewish secret listeners was shrouded was thus not lifted for another half century. By the time it became public knowledge, many had passed away. Most, therefore, never received public acknowledgment for the crucial part they played in the defeat of Nazism.
But for Fry, these declassified recordings are much more than historical artifacts.
“The transcripts of bugged conversations have a deep significance and relevance for today,” Fry told The Times of Israel. “They are independent and irrefutable evidence to be cited in the fight against Holocaust denial and anti-Semitism. I would like to see this evidence used in Holocaust education and become more widely known in our society.”
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