The Rest Is Classified - 29. The Spy Who Betrayed Oppenheimer: Deception at Los Alamos (Ep 3)

Episode Date: March 17, 2025

How did a Russian spy end up at the heart of the Manhattan Project? What happened when Soviet intelligence lost track of their own spy? And how did one man hand Stalin the bomb on a silver platter? Klaus Fuchs was already one of the most valuable spies in history, feeding atomic secrets to the Soviet Union. But when he disappeared in 1944, his handlers feared the worst. In reality, he was about to get even closer to the ultimate prize: the blueprints for the atomic bomb. This week, Gordon and David uncover how Fuchs embedded himself in Los Alamos, the most classified site on Earth, and carried out one of the greatest intelligence coups of the 20th century. ------------------- Order a signed edition of David's latest book, The Seventh Floor, via this link. ------------------- Get our exclusive NordVPN deal here ➼ www.nordvpn.com/restisclassified It’s risk-free with Nord’s 30-day money-back guarantee! Email: [e-mail] Twitter: @triclassified Assistant Producer: Becki Hills Producer: Callum Hill Senior Producer: Dom Johnson Exec Producer: Tony Pastor Learn more about your ad choices. Visit podcastchoices.com/adchoices

I used my Marxist philosophy to establish in my mind two separate compartments. One compartment in which I allowed myself to make friendships, to have personal relationships, to help people and to be in all personal ways the kind of man I wanted to be and the kind of man which in personal ways I'd been before I wanted to be, and the kind of man which in personal ways I'd been before with my friends in or near the Communist Party. I could be free and easy and happy with other people without fear of disclosing myself because I knew the other compartment would step in if I approached the danger point. I could forget the other compartment and still rely on it.

It appeared to me at the time that I'd become a free man because I had succeeded in the other compartment to establish myself completely independent of the surrounding forces in society. Looking back at it now, the best way of expressing it seems to be to call it a controlled schizophrenia. Welcome to The Rest Is Classified. I'm Gordon Carrera. And I'm David McGlasky. And that was Klaus Fuchs, atomic spy, writing years later about the way he compartmentalized his life, the betrayal he'd been carrying out and the years of deception that were involved.

Klaus Fuchs, of course, was this brilliant mathematician, theoretical physicist who'd come from Germany to the UK, who'd been a communist and anti-Nazi as well, had been interned and had got to know through this group of communists mainly based in Hampstead's leafy suburb, the Soviet Union's intelligence service, the GRU, and had been recruited effectively as he joined the atomic program of the UK and then headed over to the US. And we left him last time, didn't we, David? Having been meeting his now KGB handler, Harry Gold, codenamed Raymond as he knew him, in New York. But then suddenly, August 5th, 1944, Fuchs doesn't turn up for the key next meeting,

nor the one after that. He's disappeared. Where's he gone? Where in the world is Klaus Fuchs? I do like Gordon how in the upsum there you just sort of brushed over his communism. That was sort of the fifth adjective that was raised in describing Klaus Fuchs. But yes, he's gone missing. It is August of 1944, the 5th of August actually, when Klaus Fuchs misses his meeting with Raymond, also known as Harry Gold,

his KGB handler. And of course, the Soviets are concerned by this, Gordon. This is their spy inside the Manhattan Project. So probably one of, if not the most valuable spy that the KGB is running at that time. And he's gone. And unlike many of the kind of human assets that would be run today, he doesn't have a device to communicate with the KGB. He's doing it by the sort of complicated system of scheduled meetings and verbal paroles, and he's just gone, poof, he's gone. Now, what Raymond does is he, you know,

eventually gets very concerned by this. And in fact, Fuchs has missed a backup meeting. And Raymond is gonna go to Fuchs' apartment, carrying a book as kind of a cover to say that I've come to return this to you. But really, he's trying to check out Fuchs's apartment in New York. And he finds out from the neighbors that Fuchs has left to go somewhere on a boat, which, of course, sounds like he's going back to Great Britain.

And that would be extremely disappointing from the perspective of the Soviets because the other option at this point was for Fuchs to go to site Y, which is Los Alamos, where Robert Oppenheimer and a team of physicists and engineers and mathematicians and scientists are actually building the bomb. And so what Raymond does is he goes next and he visits Klaus Fuchs' sister, Christelle,

who's in Massachusetts, in Cambridge. Not your Cambridge, Gordon, the Cambridge with a better educational institution, Harvard University. I'm aware of it. I may have even been there. And he learns that Fuchs had actually gone to see Christelle and say goodbye. And so Harry Gold Raymond says, we've lost contact with rest, which is the code name for Klaus Fuchs. And it's worth just saying that Christelle is quite an interesting character and quite an important character. Klaus Fuchs, his sister who's left Germany, ended up in America in the 30s. And she is, stand by, going to play a role again later in

the story, isn't she? So worth remembering Christelle. But yes, she's the kind of fallback contact effectively, which allows Harry Golden, the KGB, to reconnect with Klaus Fuchs and to find out where he really is. That's right. Well, and surprise, Klaus Fuchs has not gone to England, despite what his neighbors said. Klaus Fuchs has gone to Los Alamos. He arrives in Santa Fe in the late summer of 1944, and he becomes a member of Oppenheimer's team out there building the bomb. Now, Los Alamos at this point is very interesting

because essentially it is where Leslie Groves, who's Matt Damon in Oppenheimer, he has hidden all of his German scientists out there so that the German scientists in Nazi Germany can't find them and won't figure out what they're doing. And it's an enormous site, isn't it? I mean, there are thousands and thousands of people there. And it is a fascinating place, I find, because it is, on the one hand, the most secret place

on earth, effectively, at this time. I think that's fair to say. And yet it's a kind of like a university campus as well, in which people bring their families and which Groves, I think, originally had wanted them all to be kind of separate and people not to meet. But all the scientists are like, no, no, no, we need to talk to each other. We need to share ideas. And so it's this kind of bubble in which once you're inside it, it's a kind of quite a free and open community. And yet it is completely secret to the rest of the world. There are 12 Nobel laureates working there, Gordon. Fuchs, I think we could say, is actually probably on the

Los Alamos B team, I would argue. You know, he's not one of the most prominent guys there, but he has access to your point on kind of the university campus feel of the place. It's sort of a university campus meets a military base. In the middle of the desert. The site was kind of an old ranch school, the Los Alamos Ranch School, which had been this kind of educational institution for very wealthy and man, Gore Vidal was actually a graduate of that and the dormitory, the big house as they call it, becomes the residence for single men. Now interestingly enough, the average age at Los Alamos, Gordon, do you know what it was in 1944? I'm guessing it's pretty young. It's pretty young.

It's 25. Wow. So it is a bunch of young scientists and military officers out there engaged in the most secretive effort in the Western world at that point. It is 45 miles outside of Santa Fe. I think the film Oppenheimer is actually filmed at Los Alamos. And so you get a good sense of the kind of geography. It's this kind of mesas and canyons and sagebrush, the desert.

It's really gorgeous country and it is completely remote, right? So Fuchs is there, late summer 1944. He is working in the theoretical division under his friend, mentor, and former landlord Rudy Piles. And he's working in Division X, the explosives group. And basically what he is doing is he's running calculations for the design of explosive lenses. Now, in the last episode, we explained in very technical and accurate terms how you construct an atomic weapon. And what we do have to add in here, and again, there's a great scene in Oppenheimer on this point where Oppenheimer is building a plutonium bomb. And if you remember from the movie, there's kind of these two fishbowls that Gillian Murphy's character plunks marbles into to show how long it's going to take the enrichment plants to generate enough plutonium and uranium for these

explosive devices. You need less plutonium than you need uranium. And so they are building a bomb out of plutonium with its fissile material. And essentially what Fuchs is working on and why he's been pulled in from New York and not sent back to Great Britain is that he's going to build the explosive lenses that sit around this plutonium core and that will really create or start the chain reaction of plutonium that generates the nuclear explosion. To compress it perfectly. It is a very important job and a very sensitive job at the heart of it despite you describing him being on the B team. But he is in the heart of the work of it and also

life in Los Alamos. He's there. He does some excursions, I think. He does some babysitting, I think, for some of the other scientists. It's a weird community, isn't it, that's living there? Yeah, it is. He does have a community there. He dates a couple of the grade school teachers in the town connected to the base, though never really forms a long-term relationship with any of them. We're painting a picture here, like they've got loads of free time at Los Alamos, and that's absolutely not true. But in the very brief downtime that they do have, you know, there's horseback riding, there's skiing, there's fishing, Fuchs goes on excursions with the piles is, and he is noted as being a real risk taker in terms of the degree of difficulty in his climbs. He's also noticed at one point, I guess he'd

been skiing and he'd injured himself while he was going down the mountain. And he was noted as sort of just continuing to ski through the pain and so I think you do get some insights into him Despite again what I described is like a very nerdy appearance very introverted. He's a very tough guy Mentally and physically noted as a skilled dancer skilled dancer Yeah I mean again doesn't fit with the slightly nerdy image, does it? A leader of conga lines with good rhythm who could also drink massive quantities of alcohol. None of this quite fits with the nerdy image, does it, that we'd kind of built up of him, of this very kind of earnest

serious guy. He was done a great disservice in the Oppenheim movie. I went back and have been watching it here as we're putting this episode together for the brief intervals in which we actually see the Klaus Fuchs character. And you really see him mostly at Los Alamos. In I think the few lines he has in the movie, Oppenheimer is sort of greeting him outside Los Alamos. And Oppenheimer says, how long have you been British? Because obviously the name Klaus Fuchs doesn't exactly scream English gentleman. And the Fuchs character says, since Hitler decided I wasn't German, right?

And so then he's sort of embedded into the community there. And there is a actual party scene at Los Alamos where I thought it was very uncharitable to the actual Fuchs because he's kind of just off in the side of the room. There's someone else playing the bonga drums, everyone's dancing, and Fuchs looks very German and introverted off on the side and then actually it's not the case. It's very harsh on the Germans. I know.

I'm being cruel to the Germans. I'm sure there's lots of fun loving Germans out there, but I have yet to meet too many of them. Okay. But Fuchs in this time, he's a massive consumer of alcohol, which is one of the themes of his time at Los Alamos. I think many of the scientists were boozing pretty hard out there. He also likes women and he's very interested in dating and spending time with women.

It's interesting, as you said earlier, it doesn't really form long-term relationships. But amidst all the conga lines and the boos, he's also going to return to his other job, which is spying. And so he's been out of touch with Raymond and his handler for, I guess, a few months. But then in the new year, he's able to reconnect. And again, it's through his sister, isn't it, in Cambridge, Massachusetts. And that becomes the way in which they're reconnected to kind of resume the spying and the espionage.

That's right. Yeah. And again, to your point on Christelle, Klaus's sister being critical to this, it's absolutely true. So Raymond, his handler returns to Christelle's home in the fall of 1944. And this is a few months after Klaus went to New Mexico, went to Los Alamos. She doesn't know where Klaus is, but Gold slash Raymond comes back to Christelle's home a few weeks after that visit in October

and discovers that Klaus had actually in the interim gone to Chicago and he'd phoned his sister. And he had told Christelle that he was in New Mexico and he's going to come and visit her at Christmas for a few weeks and then, you know, maybe we'll travel to New York. And so this is phenomenal news from the standpoint of Soviet intelligence because they now know that Fuchs is embedded in the Manhattan Project at Los Alamos and that there is a way to re-contact him

when he comes to visit his sister. And what ends up happening here is that his Christmas leave in 1944 is postponed, but in February, he ends up taking it and he goes to see Christelle in Cambridge, Massachusetts, calls Raymond, who then shows up. And at this point, in early 45, they make plans for Raymond to meet Klaus down in Santa Fe. And they work out a kind of, again, a system of passwords. Klaus actually has a map for Raymond to show him where to meet him in Santa Fe.

And Fuchs then hands over several pages of notes that he's written from memory on the bomb that they're constructing at Los Alamos, how they're using plutonium, and really critically, this implosion device that he is so critical in designing. And there's actually some scenes in the Oppenheimer movie where you see Fuchs involved in some of the tests around this explosive device, because really it's a massive engineering problem to generate or to create this kind of series of very finely calibrated explosives that really have to be totally and perfectly symmetrical, sufficiently powerful, and perfectly timed. Because if they're not, essentially what ends up happening, to use a technical term Gordon, is that some of the

plutonium will squirt out and it won't actually generate the right chain reaction inside the plutonium to create the nuclear explosion. So the explosive device is critical. To avoid squirting out of plutonium. To avoid plutonium squirting out. Thank you for that. I'm sure that's exactly how Klaus Fuchs put it in his notes. But I think the point being, it's pretty important stuff in terms of how to make a nuclear bomb.

And he's handing it over to Raymond. So they're back in touch. And I mean, there's an interesting bit, isn't it? Raymond tries to give Fuchs some money, I think $1,500 at one point, and Fuchs doesn't want to take it. Yeah, he's really angry actually. It's a classic thing where the handler wants to kind of create the kind of compromise that comes from accepting money.

But Fuchs is clearly making his point that he's ideologically motivated. I do like the fact though that his one request is that when Russian soldiers take Germany, he wants them to destroy the Gestapo files which might refer to him. It's very interesting because he knows that in that might be references to his communist past. He's a kind of sharp operator in that sense, isn't he? I think it's worth a note here that over the nearly four years that he's been working for the Soviets, I think we see an improvement in his tradecraft. We've come

a long way from the guy who was showing up at the Soviet embassy in London with documents on the atomic project. He's building the tradecraft with Raymond. He's actually setting up a very clever system to communicate with him involving a sister. So like, I think Fuchs has advanced, I think, in his career as a spy. And so in the spring of 1945, of course, this is an absolutely critical time for Klaus Fuchs and Los Alamos and really the entire world because what's happened is that the Nazis have collapsed, Hitler and Mussolini die. On the 7th of May, the Germans surrender unconditionally and what you see at Los Alamos and there's actually again in Oppenheimer there's a scene that plays out just like this. Many of the scientists now think the rationale for

building the bomb is gone, right? Because the Germans have collapsed and work on this weapon should stop. Yeah, and because if you look at it from Klaus Fuchs' point of view as well, you could justify it in terms of trying to get the bomb first to both defeat the Nazis and get it before they did. Now that threat has gone. There is this question, I think some of them start asking, which is why are we keeping on going with this? Because the kind of deterrent reason seems to have gone. But of course, the reason is the war with Japan is still going. And I think that starts to introduce, I think, not just Fuchs, but some of the scientists, some deeper moral questions about what they're doing. But for him, I guess it makes him even more determined to keep going, probably at that point.

I mean, also the other thing that's happened that spring is that Franklin Roosevelt's dead and he dies in April. And I think Fuchs had considered Roosevelt to be a wise and moral leader. Harry Truman takes over. I'm not sure Fuchs at the time had an opinion on him, but later he's going to call Truman ruthless. And I think there's a sense probably among many of the scientists at Los Alamos that they're delivering a super weapon to a untrustworthy

new president. Isn't the fascinating bit about Truman that he didn't know about the bomb project? So he didn't know, even though he's vice president, that the Manhattan Project existed or that they were developing a bomb. And the fascinating fact is, of course, Truman didn't know until he gets briefed when he takes over. Stalin did know about the Manhattan Project and everything about it, thanks to Klaus Fuchs. So Stalin actually knows more than, you know, the new president at the moment he takes over of the United States. But there we go. That's all thanks to Fuchs. Well, and I think a lot of these events of that spring come to a head on the 2nd of June 1945, which is an absolutely incredible day in espionage history. Now, we didn't mention earlier, but Fuchs, when he moves out to Los

Alamos, buys a $50 Buick that one of his Soviet handlers will later call dilapidated. It's a blue Buick. And it seems that Fuchs has been using this primarily for booze runs into Santa Fe. So he would frequently drive into Santa Fe and buy booze for, you know, many of the scientists at Los Alamos and then bring it back in. And it's a very pleasant summer day in the high desert, still a bit mild at that point. It's not, you know, if you're thinking like scorching desert in early June, it's not quite there. It's actually very pleasant. It's the late afternoon and Fuchs has got his day pass to go into Santa Fe. He's also got a collection of kind of papers and sketches in his pocket.

It's tucked into a bulky envelope and it's written in kind of his very precise crabbed handwriting. So he leaves Los Alamos. Now, again, if you've seen Oppenheimer, you know that, okay, there's gates and fences around this. So it's not just a boozy dormitory out there in the desert. I mean, it's a military installation, right? And he stops at the gate and he gets out so the guards can search his vehicle.

He keeps all of the papers in his pocket. And again, I think for listeners of this podcast, you'll note an emerging theme here, which is if you work in a highly secretive institution, the central intelligence agency, if you're working on Soviet radars, et cetera, it's actually pretty easy to take really classified documents out with you, right? Just as a note. So yeah, let's not give people ideas, but yeah, that's right. We're not endorsing that behavior.

We're not endorsing it. We're, we're merely noting it. Yeah. The check goes without any issues. Fuchs drives out. He starts to head into Santa Fe. Now Raymond is handler is also in Santa Fe because he and Fuchs had agreed on this date back in Massachusetts in the winter

and they've actually agreed on a location. So Raymond has arrived that morning by bus, kind of lived his cover as a tourist. He's gone to the city's historical museum and then he's taken a walk and it's about 4 p.m. He's standing on the Castillo Street bridge in Santa Fe, kind of a remote spot. Harry Gold slash Raymond is a little bit nervous because he doesn't really have any good reason to be out there and as a sightseer it's probably not a place you'd spend much time. But up comes this dilapidated Buick probably smells like booze. Klaus picks up Raymond and then they drive on a little further to a side road where Fuchs parks and they have a brief talk. Now,

just before he drops Raymond off, Fuchs hands his handler the plans to the atomic bomb. And he literally has schematic sketches, the whole kind of mock-up of the thing. So it's not just the theoretical physics that sort of prove it's possible. It's also a practical manual for how the Soviets would construct a plutonium bomb triggered by this implosion device. I'm imagining one of those kind of IKEA catalogs, which you know, you put this here, you put that there and then eventually you get an atomic bomb. You need an Allen wrench. Yeah.

And some washers. And then you discover you've lost one of the screws. Yeah. And it doesn't work. But anyway, it's the plan. In a full case of beer, because it's going to be so frustrating to put together that you're going to need it. And according to Raymond's biographer,

he leaves with a splitting headache thanks to the elevation in the high desert. And then goes back to Albuquerque with the plans for the atomic bomb inside that bulky envelope, wanders around for most of the night because he can't find a hotel room. So the KGB handler literally walked around Albuquerque with the plans for the bomb in his pants because he could not find a place to sleep.

And the Soviets have pulled off one of the biggest intelligence coups in history, absolutely astounding. They have got the plans for the A-bomb. I mean, it is extraordinary, isn't it? The combination of him walking around with them in his pocket, a little bit lost. And the fact it is possibly the biggest intelligence coup in history, as you say. I mean, it's hard to imagine a single transfer of information, which is more significant in terms of espionage that's happened. I can't really think of one.

I mean, you can come up with figures for how the value of this research, but it's beyond value, isn't it? In terms of its implications for the world and for the way in which the early Cold War will play out, this is it. Well, it makes me think, Gordon, of like what the present parallel would be. If we had inside DoD or with a consortium of private tech companies working with the government, if we had plans for like a quantum computer or something like that, I guess that would be a close equivalent if the Chinese or the Russians had a spy inside that program who just delivered the plans. I mean, this is the start of the atomic age, right?

We're on the cusp of that. It just almost feels like even at present, there's almost no parallel to it. It's both the importance of the plans, but it's the moment in history that they're handed over which makes this so significant. You know, we're moments away now from the US testing, you know, the weapon for the first time. It is worth reflecting here that this is a guy, Klaus Fuchs, that the Soviets didn't really recruit.

They don't pay him. He runs himself and he's just handed over the results of $2 billion of R&D, which is what the Manhattan Project cost, which is worth about $30 billion today. So maybe there with Klaus Fuchs as the $30 billion spy. We'll take a break and we come back. We will see if he can keep up this delicate dance or if his double life is going to come crashing down around him. This episode is brought to you by our friends at NordVPN. Now, Gordon, what do you find most useful about Nord?

David, one incredibly useful feature I find is the ad blocking software. That stops you being targeted, we all know about that, by intrusive ads whenever you're browsing the internet. Along with the fact Nord blocks unwanted parties tracking me, it makes me feel much safer and confident that my privacy or my privacy is protected online. And you know how much I care about your privacy, Gordon. And you know that one feature from Nord that I really appreciate is that it also has offline protection which works even when it is not connected, meaning you can be consistently

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Get to the theater and experience the movie audiences are calling. An adrenaline rush of a good time. It's a big screen blast. Find a badass. I know, right? Nova Kane, now playing. Welcome back. We're now in July 1945 with Klaus Fuchs at Los Alamos and the US about to test for the first time

the atomic bomb. It's interesting to then put yourself in Soviet shoes to think about, okay, from the standpoint of handling Klaus Fuchs, who's going to observe this test, right? What do you have at this point? And you have the plans, which he has passed in June, but you don't actually know if it's going to work. A vast amount of the secret here is whether or not the theory is going to translate into a practical weapon. And no one knows. Even Fuchs at this point doesn't think that the bomb is going to be ready in time to use against the Japanese. I mean, he thinks that the war will be over by the time they finish the weapon, but they're

all going to find out. So it's Monday, July 16th, 1945. They're about 230 miles south of Los Alamos at a place named Alamogordo, which is basically a moonscape. It had been used as a bombing range for the US military prior to this. And the scientists are all bussed down for the test, which Robert Oppenheimer has named Trinity. Now, if you've seen the movie Oppenheimer,

I mean, this is kind of one of the climaxes really of the story, right? This great set piece of all of these scientists who have spent now a couple years working on this, who are going to see if it finally actually works, right? Now Fuchs is there, he's wearing welder's goggles to protect his eyes from the flash. In the quote you read to open the series Gordon, which is a description of this test, right? Everyone had kind of had these jerry-rigged safety precautions, right?

And in one case, the father of the hydrogen bomb has covered his face in suntan lotion. He's got these welder's goggles on and he's sitting there in like a lawn chair, you know, looking down range at the test site, which is like 20 miles away. And of course, everyone is anxious and very distracted. The Oppenheimer character in the movie says, you know, these things are hard on your heart. I mean, there's a sense that all of this could be for naught. It might not work. There's also some mild concern that the detonation would ignite the atmosphere and destroy the planet. Now storms roll in and they actually delay the test until shortly after 5 a.m.

There's Russian radio interference. The camp is using the frequency of a radio station that's off the air at night. So it picks up this Russian broadcast. And so in the background at Alamogordo, there's a Tchaikovsky Waltz accompanying the countdown to the actual test. And when it happens, one of the woman who was there named Dorothy McKibben, who's one of these gatekeepers at Los Alamos, described it as an unholy light like no one has ever seen before. And of course, the test is successful. And I think maybe

slightly in contrast to the depiction in Oppenheimer the movie, the first-hand accounts really talk about this kind of somber funereal mood. There is a physicist who plays the bongo drums on the hood of a Jeep to celebrate, but everyone is actually really quiet. Yeah. They know they've unleashed potentially death and the destruction of worlds. It's that sense of the world will never be the same after that moment. Well, and pretty soon thereafter, a petition actually goes around Los Alamos urging Truman not to drop the bombs unless the Japanese have been warned.

But of course, that's ignored. The bombs are dropped. And I think part of that decision, at least as sort of Fuchs will absorb it, was to intimidate the Russians, right? And to convince Stalin to not invade any of the Japanese islands, right? And to sort of halt. And it seems like that may have actually been effective. But of course, for Fuchs, I think this is, you know, he interprets this as a very cynical, ruthless use of this power and I think probably further encourages him to continue his efforts spying for the Russians. He's a signatory to some of the ideas that the scientists there had, which is, you know,

atomic weapons should be managed by an international body. They should be put under international control. And when none of this happens, I think Fuchs is really disillusioned with the way the American government has decided to use the bomb. And he's still there and he still keeps spying. They remain actually around Santa Fe and Los Alamos for a while after the test and even the end of the war, don't they? And Fuchs is still passing information as he prepares for his next stage,

which I guess will be going back to the UK. Yeah. So in September, so a couple months after the Trinity test, he goes into Santa Fe for another meeting with Raymond on the 19th of September. Fuchs' cover is that he's there to purchase again, another Buick load of booze for a farewell party because there's a few scientists who were leaving. And Fuchs' first words to Raymond are, well, were you impressed? And he's got, you know, with him, another mother load of intelligence to pass to the Soviets. He's got the results of the Trinity test.

He's got construction details for the bomb. And really critically for the Soviets, he has rates of production for uranium-235 and plutonium and the size of the bombs. What that allows the Soviets to do is to understand the production rate for the US for atomic weapons into the foreseeable future. He also has early info on the hydrogen bomb. Yeah, which is called the Super as it was known at the time, because that is going to be a fusion bomb rather than a fission bomb.

Let's not get into the technical details, but I think you should try. I think you should try fusion rather than fish. I just did that. But the key point is it's going to be even more powerful. And that is if you like the next stage, which I think is also going to be very influential on the Soviets to realize how far and how fast the Americans and the Brits to some extent are moving. But I mean, Fuchs' time in Los Alamos at this point is coming to an end, isn't it? And he's about to head back to the UK.

He's headed back to England, Gordon. And I think it's worth noting here that there have been massive changes in Great Britain in the time that he's been away. So Churchill's been pushed out and Britain is now sort of fully in the American shadow, I would say. And Stalin is holding Eastern Europe, right? So you maybe start to see, I don't know, some sense emerging right away that the Russians are maybe not our dear friends. Yeah, I think that's right. The Cold War is kind of starting to shape up. And you know, it's interesting, isn't it?

Because you were saying Britain's in the shadow of the US. But actually, at this point, Britain realizes it's got to build its own bomb, because the strange deal it's had with the US in which it sent all its great scientists over. But the truth is, the Americans basically turf them out afterwards and say, you know, this is our work. And they kind of downplay the role and the contribution of the Brits. And the Brits decide we need to have our own bomb effectively. You know, it's the kind of great power thing.

And famously, the Foreign Secretary, Ernest Bevin, says, we've got to have a bomb and we've got to have a bloody Union Jack flying on top of it, which I think is the British attitude is, we've got to British attitude is we've got to do it, we've got to build it, we're going to have to do it ourselves, and we're going to have to do it in secret. And of course, if you're going to do that, there is literally no one in Britain who knows more about building an atomic bomb than Klaus Fuchs. I mean, he's one of the probably top handful of people in the world who understand most about how to build it, but certainly knows more about it than anyone else in Britain. And so he's going to be vital if they're going to go undertake that project.

I was struck, Gordon, in researching this episode, that we did not provide you with the necessary inputs after the war to create your own atomic bomb. Like there was additional work to be done. I mean, we kept really the IP, I guess. I think it's pretty tough. I think we come over. after the war to create your own atomic bomb. There was additional work to be done. We kept really the IP, I guess. I think it's pretty tough. I think we come over, we give you the science, we give you a lot of help and it's like, there we go, all done, off you go. So much for the special relationship.

But you also did give us a notorious communist to embed into our project to then sell the secrets to the Soviet. Yeah, true. There's actually an interesting, I think Mike Ross Rossiter in his book, The Spy Who Changed the World, which is also about Klaus Fuchs, also gives the idea that actually, by this latter stage of his time at Los Alamos, effectively, Fuchs is also spying for Britain because he's basically getting American technical secrets, which he's going to take back and be able to use for the British program.

So it's a kind of, he's spying for the Soviets, but also in a weird way for Britain on the Americans as well. Because he's going to bring back some of that knowledge to a place called Harwell, which is going to be the home of Britain's atomic weapons program. Harwell near Oxford, Didcot, Banbury, that kind of area. And that is going to be Klaus Fuchs' new home and new base for him to work from as, you know, really significant position as the kind of head of theoretical physics for Harwell and the British program.

And at this point, it's probably worth mentioning that, I mean, Fuchs has kind of gone over the course of our story from a relatively obscure physicist, I would say. I mean, it's certainly somebody who's not one of the leaders in the field, but probably a notch down to one of the top atomic physicists in the world with real practical experience with Oppenheimer in Los Alamos building the bomb. And I think Fuchs has changed a bit here, right? His personality has changed. He's now more confident. He's shed his Edward Snowden complexion to be more sort of golden brown from the New Mexico sun. He's got more stylish clothes. He's more confident. He's got slide wrinkles, apparently, of the Trinity test that he likes to show people at parties. And Fuchs at Harwell becomes, I guess,

a little bit more of a social animal, I would say. He's very close with his boss, a guy named Herbert Skinner, and Skinner's wife, Erna. And again, Fuchs, you know, he tends to be mothered, I guess, by the wives of his scientist friends. And this relationship starts to become maybe a little bit more than mother-son. I don't think it's quite a mother-son. No, I think it's a bit more than that. I think there's a question. He spends a lot of time with Erna, Herbert Skindert's wife, and I think there is a question mark about how physical or not that might have been, but they were certainly emotionally

very close at this time. So yeah, I think you're right. I think he's kind of changed as a character to some extent. I think it's worth also just mentioning here that there are some suspicions about Fuchs which are kind of rolling around MI5 and a few people have got, you know, a few question marks about him at this stage and about his possible communist past, but it generally kind of gets dismissed by some higher-ups. Interestingly enough, one of the people who kind of downplays any of the concerns

about Fuchs is an MI5 officer called Roger Hollis. Roger Hollis ends up many years later becoming the head of MI5. And in the theory of some people was also a kind of communist spy, which I don't think he was, and there's very little evidence of that. But actually some of the evidence people end up pointing to is the fact that he kind of overlooks, you know, some of the reports about Fuchs. But essentially, you know, there's a brief period where there's, I think, some surveillance on him in 1947. But just for a brief period when at this point, Fuchs is not actually undertaking espionage

at that time in 47. So at one time, they kind of really investigate and watch him. He's not doing anything. And so the investigation falls away. But then it's at that point, or soon after that he's going to get back in touch with his KGB handlers. Well, I think it's fair to say that even if MI5 had done more, they probably wouldn't have found anything. At this point, I think they're reading as mail, they're doing some light on again,

off again surveillance. So had he even been operational, it seems unlikely they would have spotted him. But in any case, in sort of 45 and 46, there have been incidents, really counter espionage cases in Canada and the US that have resulted in dozens of arrests of Soviet case officers and agents. And there is kind of this general very early Cold War buzz, I guess you could say, that the spy games with the Russians are kind of kicking off. Now, of course, they've been going on for years, but we're now starting to see real practical examples of how widespread the KGB and sort of GRU had extended the espionage net.

And so the KGB has a program called Enormoz, Enormous, which is its code name for the atomic bomb project, because it's running a network of spies who have access to atomic secrets in the US and in the UK. And it orders all of its case officers to stand down agents that are connected to enormous. Now, Fuchs, who would have been one of these agents, has probably on his own has decided when he comes back to England and he's at Harwell to not reestablish contact immediately with the Soviets in London. He just felt it was too dangerous. And so he waits a full year before making contact in England. So he's been back for over a year.

It's been almost two years since he's seen Raymond. And he finally does decide in 1947 to reestablish contact with an old friend from, again, this sort of communist underground in Berlin, who is a, I guess what the Soviets would have called a reliable person, meaning she is not a GRU or KGB officer. She's not even really a recruited agent,

but she's someone who kind of knows how to get the information to the right people. And she's going to get him connected, get Klaus Fuchs connected with a new Soviet handler in London. And they're going to be at pubs. So one of the, one of the bits I enjoy is that I like a good pub. I like a good pub tour. I'm thinking of starting a Klaus Fuchs pub tour. A walking tour of the pubs.

The rest is classified Klaus Fuchs experience where Gordon and I lead you around pubs through London and retell this story. There's even one I think I know quite well, the Bull & Bush, which is kind of Hampstead Golders Green. It's a very nice pub, bit of a gastropub I think these days. I think there's another one which is the Nags Head, which is now the Goose, I think in Woodgreen, which is going to be important. So what's Woodgreen like?

It's London. I mean, it's not my manner. I'm a bit more of a South London boy, but yeah, I quite like the idea that they meet at pubs because you kind of think at least you might as well have a nice pint while you carry out massive atomic espy. Commit high treason. Yeah. So they set up at the then nag's head. Now Fuchs is going to meet his new handler.

So on his way, Fuchs does a very basic SDR, surveillance detection route. He's first going to kind of travel away from Woodgreen and then double back by bus and by underground. So for astute listeners of our podcast who remember the episodes about Tolkachev and the deep dive we did on SDRs, you see here that Fuchs is sort of zigzagging his route. He's varying the mode of transport to give himself multiple opportunities to check to see if he's being followed. And he's going to meet a case officer there, a KGB case officer, whose real name is Alexander Feklasov, Sasha, but he's going to call himself Eugene when he meets with Fuchs. Now, Eugene is

a very talented, kind of high-flying KGB case officer who had worked in the States and he is in the process of running his own SDR with help from another colleague from the KGB residentura. They are getting on and off buses, they're wandering through department stores, they're sort of zigzagging, they're doubling back on their tracks several times. We can see here a couple things I think are worth noting. One is the KGB has made sure that he's meeting with one of their A-Team guys. Two, the environment for espionage now in London in the wake of all of these kind of counter espionage cases that have come out in the last year and a half has made it so that they are upping their game on the trade graph. This is no longer the Philadelphia guy wandering through New York, checking his six, taking class folks to restaurants. He's being handled very professionally.

And Sasha or Eugene is going to arrive at Wood Green. He's going to familiarize himself with the streets around the Nag's Head Pub, which would also give him a chance to, you know, sort of his last chance to abort. He's probably doing some provocative things, I would imagine as well, just to see if he can draw out surveillance. And then he's going to go into the pub. Eugene is carrying a red book as his signal. Fuchs is reading the Tribune, which I think, Gordon, what would be the... A left-wing newspaper, which is a bit of a giveaway, isn't it? Reading a left-wing newspaper when you're... That seems like a mistake. That seems like maybe they should have chosen what would be the conservative-

The Times. equivalent at the time. Okay, it's the Times. Okay. And there had been apparently a verbal parole designed prior to the meeting, where Fuchs was going to comment on the Guinness being the best draft in the house, but Fuchs had apparently thought that was a bad idea, that there might be some other patrons who would say the same thing. And so Fuchs, in seeing the book that Eugene is carrying, says, I think the best British

heavyweight of all time is Bruce Woodcock. And Eugene says, oh no, Tommy Farr is certainly the best. And with that sort of match made, they go for a walk down the high road and Fuchs' espionage career is back on track. So they're back on track and Fuchs is going to hand over documents on plutonium production. I mean, you know, again, just really sensitive material is going to go over this time. So Eugene offers him some money, I think this this time and he actually takes some of it, which is kind of interesting, but only a small amount of money. But it's the beginning, I guess, of the resumption of his espionage in the UK, which is going

to go on for the kind of coming months with multiple meetings and the handing over of more and more of these documents from Harwell, which is basically going to inform the Soviets about the British bomb program this time, as well as some of the technical secrets and give them a sense of where it is. The Soviets paid a hundred quid in total for the secrets of the atomic bomb that Klaus Fuchs provided. And the hundred quid was provided at this meeting. Fuchs who of course had told his prior handler Raymond that he'd been offered 1500 bucks in the

States and had been disgusted with that and had refused to take anything. Fouke said he felt compelled in this moment, probably also because Eugene is an effective KGB case officer, felt like he had to take the money to prove his loyalty. I mean, it's sort of an astounding thing. One hundred pounds was what the Soviets paid for those plans. So these meetings go on for a while, but I think one thing worth noting just before we finish is that actually around this time, 48, 49, Fuchs' views seem to be changing somewhat.

I mean, he's actually quite happy at Harwell, isn't he? He likes the place. He likes the community. Actually his view of Britain is changing. Britain has been good to me, he says. I feel I owe it to Britain to work there. He also talks about his respect for what he calls the decency of the English, something I'm sure you'd agree with. He's also slightly becoming more disillusioned with the Soviet Union at the same time, because this is the point at which the

Soviet Union is kind of clamping down on Eastern European countries like Czechoslovakia, you've got events in Berlin. The sense that the Soviet Union is a darker place than perhaps people had realized before is also coming to light. So I think there's this interesting moment where Fuchs is actually on the cusp, perhaps, of shifting some of his worldview just at this time in 48, 49. You know. When he was due to meet Eugene, he would cry off and he'd have the cough. If we remember, that cough was the kind of the signal of the kind of inner turmoil. And I just feel like at this time, 48, 49, that that conflict is becoming more acute and the betrayal of those around him at Harwell and of Britain compared

to what he's betraying them for in the Soviet Union, that I think is becoming more difficult for him. You know, you think on the one side, he is becoming more fond of Great Britain. He's got really a family of sorts at Harwell. He's in a very, very close and likely intimate relationship with Ernest Skinner, right? And it's one of the, I mean, frankly, the longest term, probably romantic relationship that he's probably ever had in his life. And he is a respected physicist who is absolutely critical to the development of the British bomb. So he's got on that side of the ledger, all these reasons to just sort of be an Englishman and hang out and

build this thing and have these wonderful relationships. On the other side though, in the way that he's integrated in this period between 1947 and 1949 with the Soviet bomb project is also intimate because what, we're not gonna talk about all these meetings, but he's gonna meet with Eugene, his handler,

about every three months. And the way this is going to work is that Eugene shows up with questions from the Soviet physicists who are building the bomb for Stalin. And they are going to relay their questions to Fuchs, and Fuchs is going to respond to them. So in a lot of ways, to the point you made, Gordon, he is building the British atomic bomb, and he's actually on the project team for the Soviet bomb too. And so I agree with you. It's like both of these identities are very real to him. And it speaks to that controlled schizophrenia

point you mentioned at the start, which I don't think one of these two things has really taken over yet. They're both living inside him at the same time. And so in 1949, with Klaus Fuchs seemingly conflicted about his different identities, his betrayals, those different compartments, suddenly everything is going to change for him. Thanks to a major intelligence breakthrough by the US and the UK, which is going to make MI5 realise they made a terrible mistake when it came to this scientist and lead to a final confrontation. See you next time. We'll see you next time.