WW2: How Britain Ignored the Mother of All Secrets
42:39 Share

Pushkin. So I have some big news for vegans and vegetarians everywhere. It's Hellman's plant-based mayo spread and dressing. Made for people with a plant-based diet or anyone really who wants to enjoy the great taste of Hellman's real without the eggs. Hellman's plant-based is perfect for sandwiches, salads, veggie burgers, or any of your family favorites.

To celebrate, Hellman's is sharing some easy, delicious plant-based recipes at hellmans.com. Hellman's Plant-Based Mayo Spread and Dressing. Same great taste, plant-based.

I'm Malcolm Gladwell, and I'd like to take a moment to talk about an amazing new podcast I'm hosting called Medal of Honor. It's a moving podcast series celebrating the untold stories of those who protect our country. And it's brought to you by LifeLock, the leader in identity theft protection. Your personal info is in a lot of places that can accidentally expose you to identity theft.

and not everyone who handles your personal info is as careful as you. LifeLock makes it easy to take control of your identity and will work to fix identity theft if it happens. Join the millions of Americans who trust LifeLock. Visit LifeLock.com slash metal today to save up to 40% off your first year. The most innovative companies are going further with T-Mobile for Business.

Together with Delta, they're putting 5G into the hands of ground staff so they can better assist on-the-go travelers with real-time information, from the Delta Sky Club to the Jet Bridge. This is elevating customer experience. This is Delta with T-Mobile for Business. Take your business further at t-mobile.com slash now. November 1939.

It's been two months since Nazi Germany invaded Poland and one month since Poland surrendered. France and Britain have declared war, but there's not much fighting. An uneasy quiet has descended over Western Europe, with neither side keen to take major risks. It's obvious that the quiet won't last. And a German executive named Hans-Ferdinand Meyer has picked a side.

Meyer is visiting Oslo on a business trip. He doesn't look much. A neat, middle-aged fellow in a suit who works in some sort of corporate research lab back in Germany. Nobody bats an eyelid when he descends from his room to the lobby of Oslo's elegant Hotel Bristol and asks the head porter, Would it be possible, please, to borrow a typewriter? Meyer takes the typewriter back upstairs to his room.

He closes and carefully locks the door, pulls on a pair of gloves to obscure his fingerprints. What he's about to do is dangerous, very dangerous. If the Gestapo ever find out, he's a dead man. Then Meyer's gloved fingers begin to type perhaps the most spectacular intelligence leak in history.

In a terse but wide-ranging pair of reports, he describes Nazi Germany's most sensitive military technologies, their bomber production, the aircraft carrier being built in Kiel Harbor, the remote-controlled gliders fitted with large explosive charges.

Meyer deftly outlines the Nazi autopilot system which is under development and which will allow them to take down barrage balloon defences using unmanned planes. He keeps typing, describing the ballistic missiles that the German army are developing and the name of the research centre. He provides the location just north of Berlin of the R&D laboratories of the German air force, the Luftwaffe.

and suggests that it would be a rewarding target. How did Meyer learn all this? Some of it's gossip, some of it's wrong, but much of what he writes is specific, technically rigorous and absolutely accurate. And this he knows because he's the director of the Siemens Research Laboratory in Berlin, and the scientists working for him have increasingly been producing evidence

cutting-edge electronics for military purposes. Shortly after, Meyer borrows the typewriter. He arranges to have his two letters delivered to Oslo's British embassy. For the embassy staff, they're mysterious, sensational, baffling. It seems to be some of Nazi Germany's most closely guarded secrets, signed only with the curious name Martel. Who sent them? Can they be believed?

Meyer must be convinced that some deep evil lurks at the heart of the Nazi regime because he's willing to risk his life to warn the British about what the Nazi military is capable of. But will the British listen? I'm Tim Harford, and this is Cautionary Tales. MUSIC PLAYS

Ostriches do not, in fact, bury their heads in the sand when trouble is approaching, but sometimes people do. That's what this cautionary tale is all about. Why do we manage to ignore the obvious? It should have been clear that Hans Ferdinand Meyer's letters, which became known as the Oslo Report, were worth taking seriously. Yes, this mysterious Martill fellow might have been a crank.

Or the letters could have been fakes, a double bluff planted by the Nazis to deceive the British about their real capabilities. But the Oslo report included several paragraphs that could hardly be a Nazi bluff. They gave a detailed and authoritative description of German radio wave technology. At the time, the British tended to be rather sniffy about German engineering.

Yes, the Germans could do things cheaply, but they were hardly at the cutting edge. Meyer's report suggested otherwise. He explained that the Luftwaffe was developing guidance systems, using radio beams to help bombers drop their deadly payload at exactly the right spot, the equivalent of satellite navigation before satellites existed. Germany would be able to bomb British targets even at night.

Meyer also described Germany's defensive radar technology, shortwave radio transmitters, which bounced signals off incoming aircraft and used the reflections as an early warning system. If the British sent bombers over Germany, the radar stations would see them coming and Germany's fighter groups would have easy pickings.

He gave the details, the wavelengths being used, even the mathematical formulas involved. This couldn't be a bluff. At the very least, it proved that someone in Germany knew all about radar, which the British had assumed was their closely guarded secret. Radar technology would be pivotal in the Second World War, as vividly described in Tom Whipple's book, The Battle of the Beams.

Hans Ferdinand Mayer's brave decision to expose the secrets of German radar could be pivotal too, if the British took it seriously. If. In the early 1930s, a senior British politician stood up in Parliament to explain the likely course of a future war.

It is well also for the man in the street to realize that there is no power on earth that can protect him from being bombed. Whatever people may tell him, the bomber will always get through. That seemed all too true at the time. There was no defense against the new bombers that were being developed. They flew too high to be easily intercepted and would attack without warning. In 1937, the Luftwaffe seemed to prove the point.

by laying waste to the Spanish market town of Guernica, with one of the first major bombings of a civilian population. But when Guernica was attacked, the British had already been working on a secret defence for a couple of years.

And by 1939, that defence was fully prepared. An invisible network of radar stations blanketed the country, in places with reliable electricity supplies, good visibility out over the sea, and that would not gravely interfere with grouse shooting. This was Britain, after all. If the grouse shooting was disrupted, then the Nazis had already won.

These radar stations would send out pulses of invisible light, radio waves, and detect the reflection of those pulses from incoming objects. The Royal Air Force would get advanced notice of approaching bombers and could send fighters up to intercept them. Guided by radar, the outnumbered fighters of the Royal Air Force could be mustered and focused where they were most needed, the heroic few

could stand up to the mighty Luftwaffe. So when Hans Ferdinand Meyer was typing his secret Oslo report early in November 1939, radar was old news to the British. What was new and should have been a dramatic revelation was the fact that the Germans had radar too.

Meyer's brave act of espionage could save many British lives if they paid attention to the Oslo report. If not, they'd have to find out about German radar the hard way. On December 18th, 1939, a few weeks after Meyer had typed his report, it was a cold, bright day over the northwest coast of Germany and the naval base of Wilhelmshaven.

To the Royal Air Force, it was a lovely day for the precision bombing of the German fleet. Not a bomb would be wasted. Not a civilian would be harmed. The conditions were ideal. That all assumed the bombers would attack without warning. If the defenders knew they were coming, however, the clear conditions would be a double-edged sword. Splendid weather for fighters, opines a Luftwaffe fighter commander.

He's not really expecting a British attack, merely hoping for one. His assistant shakes his head regretfully. The Tommies are not such fools. They won't come today. On the tiny German island of Heligoland, less than half a square mile in size, electronic eyes have been installed. German radar there and elsewhere will give plenty of warning of any incoming bombers.

But the British, despite Meyer's warning, are convinced that only they, and not the Germans, have cracked the secrets of radar. The pilots of the 22 bombers heading towards Wilhelmshaven have every reason to believe they will catch the defenders completely unawares. When the radar operators on Heligoland notify their superiors of the incoming bombers, they're met with disbelief. You are plotting seagulls.

With the winter sun low in the southern sky, the defensive Luftwaffe fighters would have plenty of cover for their counter-attack. Could the British really be so foolish as to try something? They would. The images on the radar scope aren't seagulls. They're 22 sitting ducks. With the German fighters given so much warning by the radar system,

the incoming British bombers don't stand a chance. More than half of them are shot down, as the rest flee to safety, having barely made a dent in Germany's fleet. The utter rout of the bomber force did prompt a rethink. In future, the Royal Air Force would attack at night.

Of course, radar also works perfectly well at night. But the idea that the Germans had radar had yet to penetrate the skulls of the British elite. Cautionary tales will be back after the break. And just a warning, there will be a brief mention of suicide. AI might be the most important new computer technology ever. It's storming every industry and literally billions of dollars are being invested. So buckle up.

The problem is that AI needs a lot of speed and processing power. So how do you compete without costs spiraling out of control? It's time to upgrade to the next generation of the cloud, Oracle Cloud Infrastructure, or OCI.

OCI is a single platform for your infrastructure, database, application development, and AI needs. OCI has 4 to 8 times the bandwidth of other clouds, offers one consistent price instead of variable regional pricing, and of course, nobody does data better than Oracle. So now you can train your AI models at twice the speed and less than half the cost of other clouds.

If you want to do more and spend less, like Uber, 8x8, and Databricks Mosaic, take a free test drive of OCI at oracle.com slash strategic. That's oracle.com slash strategic. oracle.com slash strategic. I love cycling, and I'm eager to get my kids cycling too. It's a great way for them to stay fit and move around our home city independently. But of course, I also want them to be confident and safe.

which is where Guardian Bikes comes in. The bike comes in a box and it's easy to assemble with all the tools you need and simple online instructions. My son and I unboxed his bike together, spent about 20 minutes working as a team to assemble it and then he was on the bike and ready to ride.

The bike looks great and with the SureStop braking system it brakes quickly and safely without locking the front wheel and sending you over the handlebars. Guardian Bikes offer a 365-day money-back guarantee covering returns, repairs and spare parts. Join hundreds of thousands of happy families by getting a Guardian Bike today. Visit GuardianBikes.com to save up to 25% off bikes. No code needed.

Plus, receive a free bike lock and pump with your first purchase after signing up for the newsletter. That's GuardianBikes.com. Happy riding! If you're listening to this right now, you probably like to stay on top of things, which is why I want to mention The Economist. Today, the world seems to be moving faster than ever. Climate and economics, politics and culture, science and technology, wherever you look, events are unfolding quickly. But now you can save 20% off an annual subscription to The Economist,

So you won't miss a thing. The Economist broadens your perspective with fact-checked, rigorous reporting and analysis. It's journalism you can truly trust. There is a lot going on these days, but with 20% off, you get access to in-depth, independent coverage of world events through podcasts, webinars, expert analysis, and even their extensive archives. So, welcome back.

Whether you want to catch up on current events or dive deeper into specific issues, The Economist delivers global perspectives with distinctive clarity. Just to give an example, What's Next for Amazon as it turns 30? analyzes how Amazon's fourth decade looks like an area of integration for the company. Go beyond the headlines with The Economist. Save 20% for a limited time on an annual subscription. Go to economist.com and subscribe today.

Two years earlier, in 1937, relations between the German Luftwaffe and the British Royal Air Force had been cautious but cordial. Officers from each side would visit the other, chatting diplomatically about the friendship between the two great nations.

One visiting German officer took a surprisingly frank line of questioning. How are you getting on with your experiments in the detection by radio of aircraft approaching your shores? He asked his astonished hosts. He added cheerfully, We have known for some time that you were developing a system of radio detections, and so are we, and we think we are ahead of you.

The British didn't need Meyer to warn them about German radar. A Luftwaffe officer had done the same two years before war broke out. Somehow, the lesson didn't stick. So why do we sometimes deny the obvious? One answer is that maybe what seems obvious with hindsight wasn't obvious at the time. The Oslo report, coupled with the indiscreet visiting officer, should have been evidence enough...

But that's easy to say with hindsight. There would have been dozens of informants, hundreds of reports, countless rumours. Different people in the British military will have heard different things and not every piece of information would have reached the right person. Some reports would have been dismissed as junk. Some would have been too sensitive to share widely. A conversation with a visiting German in an officer's mess in 1937 might have been reported somewhere...

Filed and forgotten, or not reported at all. Amidst all the noise, it can be difficult to pick out the signal. In their book Predictable Surprises, Max Bazerman and Michael Watkins call this an integration failure.

An organisation may have all the information it needs, but sifting out what really matters and assembling those disparate clues into the true picture can be a near impossible task. The British weren't the only ones to suffer integration failures.

The Germans, for example, regarded their radar system as the mother of all secrets. Yet they also published publicity photographs showing radar aerials clearly visible. This was because the radar system was so secret that the German censors weren't told that it was a secret. Nor were the Americans immune.

In fact, the most famous intelligence failure of the war was arguably an integration failure. The Japanese attack on Pearl Harbor came as a complete surprise to the US forces there. Shouldn't the Americans have seen the Japanese coming? The clues were there. Several American and British strategists had warned that Pearl Harbor would be a tempting target for a Japanese attack.

US-Japanese relations were extremely tense and war seemed a distinct threat. An American codebreaker, Genevieve Grotian, had cracked a Japanese diplomatic code six weeks before the attack. She exposed a message between the Tokyo government and the Japanese embassy in Washington, noting, "...there is more reason than ever before for us to arm ourselves to the teeth for all-out war."

Just a week before the attack, another message was deciphered. The Japanese ambassador in Berlin was instructed by Tokyo to warn Adolf Hitler that...

With hindsight, this all seems very obvious. So obvious, in fact, that some people believe in a conspiracy theory that the US or the UK deliberately ignored the warnings in the hope that Japan would attack and American voters would support the US entering the war. The truth is more prosaic. There were lots of hints of trouble, but lots of noise and false alarms too. Different decision makers had different clues –

And these clues didn't reach the right people at the right time. In her influential book about Pearl Harbor, the historian Roberta Wollstetter wrote, "...it is only to be expected that the relevant signals, so clearly audible after an event, will be partially obscured before the event by surrounding noise."

Perhaps the British failed to understand that the Germans had radar because they were simply suffering an integration failure. If so, they were about to get another very clear signal amidst the noise. In December 1939, the same month as the disastrous raid on Wilhelmshaven, and six weeks after Hans Ferdinand Meyer's letters...

Another German named Hans would present the British with another opportunity to learn what they faced. This fellow is Hans Langsdorff, captain of the Graf Spee, a mighty German battleship.

the Graf Spee had been prowling around the South Atlantic, sinking merchant ships after first allowing their civilian crews to disembark. Captain Langsdorff regarded naval warfare as a matter of honour, after all. Still, he was avoiding a real fight, since German naval doctrine at the time was to attack only civilian ships, causing maximum trouble for minimum risk.

Captain Langsdorff and the Graf Spee were causing a lot of damage to the Allied war effort, and the Royal Navy resolved to hunt them down near the huge River Plate Estuary, where Argentina, Uruguay and the Atlantic Ocean meet. Just after dawn on 13th December, three British cruisers spotted the Graf Spee's smoking funnel on the horizon and gave chase. That was a brave move,

Even with three against one, the Graf Spee was a larger, better armed and armoured ship, a formidable opponent. Graf Spee concentrated its fire on one ship, the Exeter, and within minutes Exeter had lost the torpedo crews, communication systems, an entire gun turret and most of the men on the bridge. Exeter's captain was lucky to survive, wounded in both legs and both eyes.

The British pulled back to assess the situation. Graf Spee had been hit more than 20 times, but the damage seemed superficial. The British didn't know that they'd been lucky. One of Exeter's shells had shattered Graf Spee's fuel-filtering plant.

The German battleship would run out of fuel within hours. Graf Spee dashed towards Montevideo, the nearest port, which was in neutral Uruguay. Once there, Captain Langsdorff frantically tried to repair his battleship, while the British scrambled to assemble reinforcements. Langsdorff was alarmed when he was informed that a British communication had just been intercepted.

The British ambassador to Uruguay had ordered fuel in order to supply the new British battleships that were arriving. Langsdorff's crew were starting to panic. One officer was convinced that, gazing out from Montevideo, he'd seen lurking on the horizon not only a British battleship, but an aircraft carrier and three destroyers.

What none of them knew was that the ambassador's fuel order was a bluff. Knowing his communications would be intercepted, he'd paid for fuel for ships that didn't exist. Langsdorff fell for it and bowed to what seemed inevitable. He limped the graft spay out to the river plate estuary, planted explosives on her hull and sent her to the bottom of the sea.

Sadly for Captain Langsdorff, the bottom of the sea was only 12 yards down. Most of the ship remained above the surface and photographs of the burning wreck went around the world, gleefully exploited by the British for propaganda purposes. For Captain Langsdorff, an honourable man, it was a final humiliation. From a hotel room in nearby Buenos Aires, he wrote a letter to his wife and another...

to his parents. The third letter was addressed to the German government. "For a captain with a sense of honour, it goes without saying that his personal fate cannot be separated from that of his ship," he explained. Having written the three letters, he spread the Graf Spee's Ensign flag out on the floor, lay on top of it and shot himself. Out across the river plate estuary, the smoke from the Graf Spee began to clear.

As it did, a sharp-eyed observer in British intelligence noticed something curious in the latest photographs. What was that mysterious network of criss-crossing wires on Graf Spee's forward tower? It was now January 1940.

Let me introduce you to a British radar scientist named Labouchere Hilliard Bainbridge-Bell. I hope you'll forgive me if I just call him Bainbridge-Bell. He thought the array on the Graf Spee looked suspiciously like a radar system. He flew to Uruguay to find out more. When Bainbridge-Bell arrived in Montevideo, his James Bond-style cover story was that he was a scrap metal dealer.

British intelligence had already purchased the salvage rights and Bainbridge Bell rode out to Graff's Bay to examine his property. Although the ship had already been picked over by scavengers and gutted by fire, he was relieved to discover that the radar tower still contained many clues. For radar tower, it undoubtedly was.

as he stood on the sloping deck amidst the wreckage. Bainbridge Bell gazed around at the fragments of a cathode ray display and sifted through the gears and the electronics that lay scattered around. His report back to the British government was unambiguous. The writer's personal opinion is that the installation was a 60cm RDF. Radar.

It seems strange that no-one was curious before January 1940 about the aerial on the control tower. Strange indeed. But as Tom Whipple explains in The Battle of the Beams, the lack of curiosity would continue. The report was filed and then forgotten. Not only had Hans Ferdinand Meyer warned the British that the Germans had radar...

But Bainbridge Bell had seen the radar with his own eyes. The official position of the Royal Air Force, however, did not change. Britain, and Britain alone, commanded the miracle technology of radar. Cautionary Tales will be back after the break.

I love cycling and I'm eager to get my kids cycling too. It's a great way for them to stay fit and move around our home city independently. But of course, I also want them to be confident and safe, which is where Guardian Bikes comes in. The bike comes in a box and it's easy to assemble, with all the tools you need and simple online instructions. My son and I unboxed his bike together, spent about 20 minutes working as a team to assemble it

And then he was on the bike and ready to ride. The bike looks great and with the SureStop braking system it brakes quickly and safely without locking the front wheel and sending you over the handlebars. Guardian bikes offer a 365-day money-back guarantee covering returns, repairs and spare parts. Join hundreds of thousands of happy families by getting a Guardian bike today.

Visit GuardianBikes.com to save up to 25% off bikes. No code needed. Plus, receive a free bike lock and pump with your first purchase after signing up for the newsletter. That's GuardianBikes.com. Happy riding! If you're listening to this right now, you probably like to stay on top of things, which is why I want to mention The Economist. Today, the world seems to be moving faster than ever. Climate and economics, politics and culture, science and technology, wherever you look,

Events are unfolding quickly, but now you can save 20% off an annual subscription to The Economist so you won't miss a thing. The Economist broadens your perspective with fact-checked, rigorous reporting and analysis. It's journalism you can truly trust. There is a lot going on these days, but with 20% off, you get access to in-depth, independent coverage of world events through podcasts, webinars, expert analysis, and even their extensive archives. So where

Whether you want to catch up on current events or dive deeper into specific issues, The Economist delivers global perspectives with distinctive clarity. Just to give an example, What's Next for Amazon as it turns 30? analyzes how Amazon's fourth decade looks like an area of integration for the company. Go beyond the headlines with The Economist. Save 20% for a limited time on an annual subscription. Go to economist.com and subscribe today.

By February 1940, it should have been brutally obvious that the Germans had radar, but the British refused to believe it. The delay was costly. Just ask the surviving crew of HMS Delight. This British destroyer ventured out of a harbour on the south coast of England in the summer of 1940 and within a few miles was sunk by German dive bombers.

Six sailors died. How unlucky, thought the British. But it wasn't bad luck. It was good German radar. The same story could be told by the crews of British bombers. In 1940, the British weren't in a position to bomb the Germans very often. But when they did, the losses were unexpectedly grievous. How unlucky.

If the British had woken up to the obvious, the true source of these losses would have been recognised, and some of them could have been prevented. If you understand that an enemy has radar, you can start to take precautions. Flying decoy missions, or flying in formations that overwhelm the radar operators, or trying to jam the radar electronically, or fill the sky with false signals.

Later in the war, both sides became masters of such tricks. But at the start, the Nazis were racing to develop countermeasures to British radar, and the British didn't even know there was a race at all. So why did it take the British so long? Was it just an integration failure? Were different parts of the British military receiving different signals? And were they unable to put them all together and spot the pattern amidst the noise?

I discussed this question with Tom Whipple, the author of The Battle of the Beams. He pointed out that there was one British intelligence analyst who didn't have any trouble at all piecing together the pattern. His name was R.V. Jones. If you've heard our series on the V-2 rocket, R.V. Jones was the man who rightly warned Winston Churchill that Germany was developing the V-2 ballistic missile at Peenemunde.

Jones was just as sharp on the question of German radar. He didn't miss much. In May 1940, he informed his colleagues that it was "almost certain" that Germany had radar. In July 1940, he wrote another short report summarising the evidence. A prisoner of war had admitted that the German navy had range-finding radar.

German planes had been spotted with what seemed to be radar systems. Eavesdropping on German radio revealed that pilots were celebrating the use of a codename system to successfully intercept British planes. And of course, there was the Oslo report and the discovery of a fragmentary radar system on the Graf Spee. R.V. Jones declared, It is safe to conclude that the Germans have an RDF system. They had radar.

Jones pulled together much of the relevant evidence, drew the obvious conclusion in plain language and circulated his analysis to Winston Churchill's chief scientific advisor and several other senior people. This wasn't a Pearl Harbor situation. It wasn't an integration failure. The men who needed to know the truth were told it and they refused to believe. Early in 1941,

A mysterious figure was seen standing on the south coast of England, pointing a mysterious array of aerials out over the sea towards occupied France. The locals were alarmed, and this dastardly fellow was soon in the custody of the police as a suspected German spy. He was, in fact, a frustrated British scientist named Derek Garrard.

Garrard was waiting to receive permission to join the intelligence team of the formidable R.V. Jones, but his security clearance had been slow to arrive, and Derek Garrard was in a hurry. There was a war on, after all. He convinced the police to release him and headed straight back to the coast to set up his equipment again. He was listening for the distinctive pulses of a German radar system.

RV Jones, meanwhile, had been shown a pair of aerial photographs with a strange anomaly in them, a blur that suggested a rotating object. Jones already suspected that the site in question on the French coast might contain a radar station. He requested that a Spitfire fighter pilot make the dangerous journey over the sea to get a close-up photograph of the strange object.

The pilot returned and complained that all he'd found was an anti-aircraft gun, a gun which could have killed him. But when the photographs were examined, they showed not only the gun, but off in the background, at the edge of the image, a radar. Jones had seen the enemy. And Derek Garrard had heard it. The very same radar station that the Spitfire pilot had photographed.

As Jones was studying that photograph, Garrard burst in, breathless with news that his aerials on the south coast had clearly picked up the radar signal. This might come in handy. Jones was due at a meeting later that day, called by the Royal Air Force's Head of Radar and Signals. The agenda for the meeting? Did the Germans have radar? At the beginning of the discussion, that was still an open question.

When RV Jones strolled in with Garrard's report of listening to the radar in one hand and the Spitfire pilot's photograph of it in the other, the question had finally been answered. It was February 1941, 15 months after Hans Ferdinand Meyer had borrowed a typewriter and risked his life to warn the British that the Germans had radars.

RV Jones didn't suffer fools gladly, but he was diplomatic enough not to name the fools. Shortly after the war, he dryly wrote: Prejudice is the right word.

Too many of the people who mattered had already made up their minds that the Germans couldn't have radar. The original sins here were pride and wishful thinking. Pride in British ingenuity meant that British scientists and officers were reluctant to admit that German technology might be just as good as theirs. And wishful thinking, the hope that the fearsome German war machine had a weak spot, their lack of radar.

And because the British were so determined to disbelieve in German radar, they found fault with every piece of contrary evidence that crossed their desks. Those bulges on German planes weren't radar, they were just bulges. The Oslo report was clearly unreliable, a Nazi bluff. Evidence from interrogated prisoners couldn't be trusted. Psychologists call this biased assimilation of information.

Claims that support your views are seized upon without question. Contrary evidence is dismissed or explained away. This is a sadly familiar story to connoisseurs of cautionary tales. We all have fond beliefs, and we're at risk of mental contortions to protect those fond beliefs.

Even as the British started to wonder if the Germans really did have radar, their pride wouldn't let them admit that the Germans might have figured it out all by themselves. Winston Churchill asked the Air Ministry to check that no British radar had been captured during the fall of France. I understand there were two or three British radar sets. Can I be assured they were effectively destroyed before evacuation?

He was right to ask. The Germans had indeed managed to seize a British radar. While sweeping across Belgium and France in May and June of 1940, German radar engineers had taken it apart and examined it closely, before concluding that the British technology was so crude that they had nothing to learn.

After the war, R.V. Jones tried again and again to figure out who had written the Oslo report. In the end, he gave up, assuming that the anonymous author had been killed in the war, or perhaps executed as a traitor. Hans Ferdinand Meyer had been arrested by the Gestapo in 1943, but not because of the Oslo report.

His crime was listening to broadcasts from the BBC. A neighbour's maid overheard him repeating something critical of the Nazi regime from one of those broadcasts, and that was Meyer's undoing. Meyer was sent to Dachau, a concentration camp, where he was put to work trying to develop counterintelligence in a radio research laboratory. He kept his head down.

As the regime began to fall apart at the end of the war, Hans Ferdinand Meyer simply walked out of a prison camp and into the safety of a nearby wood. Meyer knew that some people would view him as a hero and others as a traitor. So he preferred to keep his authorship of the Oslo Report a closely guarded secret.

But through an extraordinary set of coincidences, R.V. Jones finally learned his identity and tracked him down in 1955. He was living in Munich and, once again, running a research lab for Siemens. One evening, over quiet conversation in Meyer's apartment in Munich, Jones asked him why he'd done what he'd done. Why had he taken such extraordinary risks?

There's a political answer and a more personal one. The political answer is simply that Meyer was a staunch anti-Nazi. The personal answer is that Meyer had a friend in Britain, another electronics expert named Henry Cobden-Turner. When the Nazis rose to power, Meyer and Cobden-Turner worked together to rescue a half-Jewish girl named Claudia Martyl Karweich.

whose Jewish mother had been expelled from Germany and whose Nazi father had disowned her. At Meyer's request, Cobden-Turner managed to get a visa and a British passport for her, and she was saved, eventually moving to New York and living a long and happy life in America. Meyer and Cobden-Turner became the most loyal of friends.

Cobden-Turner was godfather to Meyer's son. Cobden-Turner urged Meyer to leak German secrets to help bring down the Nazis, but Meyer refused. It wouldn't be right, he insisted, unless the countries were actually at war. And once war came, it was impossible for him to reach Cobden-Turner directly. Hence the pretext to visit Oslo, the borrowed typewriter, and the mysterious letters to the Oslo embassy.

Meyer always hoped they might get into Cobden-Turner's hands, since he was a radio expert himself. That was why the letters were simply signed Martill, the middle name of the girl they'd saved together. Cobden-Turner was the only man alive who would understand the reference. R.V. Jones listened to all this, and then he kept Meyer's secret for decades, until both Meyer and Meyer's wife were dead.

The Oslo report, he said, was probably the best single report received from any source during the war. But that quiet evening in Munich, did R.V. Jones tell Meyer that the British simply hadn't believed the Oslo report and that the Royal Air Force was still debating the existence of German radar more than a year later? I hope not.

Meyer had risked everything to warn the British. It would have been cruel to tell him that the British simply hadn't listened. This cautionary tale is based, with permission, on Tom Whipple's book, The Battle of the Beams. It's a vivid and surprising history, and there's a lot more to it than the argument about German radar. Pick up a copy if you can.

For a full list of our sources, as always, see the show notes at timharford.com. Coercionary Tales is written by me, Tim Harford, with Andrew Wright. It's produced by Alice Fiennes, with support from Marilyn Rust. The sound design and original music is the work of Pascal Wise. Sarah Nix edited the scripts. It features the voice talents of Ben Crow, Melanie Guttridge, Stella Harford, Gemma Saunders and Rufus Wright.

The show also wouldn't have been possible without the work of Jacob Weisberg, Ryan Dilley, Greta Cohn, Vital Mollard, John Schnarz, Eric Sandler, Carrie Brody and Christina Sullivan.

Cautionary Tales is a production of Pushkin Industries. It's recorded at Wardour Studios in London by Tom Berry. If you like the show, please remember to share, rate and review. Tell your friends. And if you want to hear the show ad-free, sign up for Pushkin Plus on the show page in Apple Podcasts or at pushkin.fm.com.

I'm Malcolm Gladwell, and I'd like to take a moment to talk about an amazing new podcast I'm hosting called Medal of Honor.

It's a moving podcast series celebrating the untold stories of those who protect our country. And it's brought to you by LifeLock, the leader in identity theft protection. Your personal info is in a lot of places that can accidentally expose you to identity theft. And not everyone who handles your personal info is as careful as you.

LifeLock makes it easy to take control of your identity and will work to fix identity theft if it happens. Join the millions of Americans who trust LifeLock. Visit LifeLock.com slash metal today to save up to 40% off your first year.

So I have some big news for vegans and vegetarians everywhere. It's Hellman's plant-based mayo spread and dressing. Made for people with a plant-based diet or anyone really who wants to enjoy the great taste of Hellman's real without the eggs. Hellman's plant-based is perfect for sandwiches, salads, veggie burgers, or any of your family favorites.

To celebrate, Hellman's is sharing some easy, delicious plant-based recipes at hellmans.com. Hellman's Plant-Based Mayo Spread and Dressing. Same great taste, plant-based.

The news isn't always good news, but when you're getting quality journalism and in-depth expert analysis that's held up for more than 180 years, that is definitely good news. So if you haven't already, save 20% with The Economist's summer sale today and stay on top of the stories that matter to you. You'll instantly gain unlimited digital access to daily articles, special reports, award-winning podcasts, subscriber-only events, and so much more. Now that's

Good news. Go to economist.com and subscribe today.