The Rest Is Classified - 182. The Imitation Game: The Codebreakers Who Defeated Hitler (Ep 2)

Episode Date: August 5, 2026

Alan Turing is working frantically to break the German codes at Bletchley Park. But can the Brits and Americans really trust each other? Listen as David and Gordon conclude their two-part exploration of the incredible work undertaken at the predecessor to GCHQ. ------------------- THE REST IS CLASSIFIED LIVE 2026 at The Rest Is Fest: Buy your tickets ⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠⁠ to see David and Gordon live on stage at London’s Southbank Centre on 4 September: ⁠⁠⁠⁠https://www.southbankcentre.co.uk/whats-on/the-rest-is-classified-live/⁠⁠⁠⁠ ------------------- Sign-up for our free newsletter where producer Becki takes you behind the scenes of the show: ⁠⁠⁠⁠⁠⁠⁠https://mailchi.mp/goalhanger.com/tric-free-newsletter-sign⁠-up⁠⁠⁠⁠⁠⁠ ------------------- Join the Declassified Club to go deeper into the world of espionage with exclusive Q&As, interviews with top intelligence insiders, regular livestreams, ad-free listening, early access to episodes and live show tickets, and weekly deep dives into original spy stories. Members also get curated reading lists, special book discounts, prize draws, and access to our private chat community. Just go to ⁠⁠therestisclassified.com⁠ or join on Apple Podcasts. ------------------- Get a 10% discount on business PCs, printers and accessories using the code TRIC10. Visit ⁠⁠⁠⁠https://HP.com/CLASSIFIED⁠⁠⁠⁠ for more information. T&C's apply. ------------------- EXCLUSIVE NordVPN Deal ➼ https://nordvpn.com/restisclassified Upgrade your online protection with an all-in-one security app! It’s risk free with NordVPN’s 30-day money-back guarantee 🌍 ------------------- Email: ⁠⁠⁠⁠⁠[e-mail]⁠⁠⁠ Instagram: ⁠⁠⁠⁠⁠⁠⁠⁠@restisclassified⁠ Video Editor: Joe Pettit Social Producer: Emma Jackson Assistant Producer: Alfie Rowe Producer: Becki Hills Head of History: Dom Johnson Exec Producer: Tony Pastor Learn more about your ad choices. Visit podcastchoices.com/adchoices

For exclusive interviews, bonus episodes, ad-free listening, early access to series, first look at live show tickets, a weekly newsletter, and discounted books. Join the Declassified Club at the Rest is Classified.com. A secret mission to Bletchley Park, but can the Brits and Americans really trust each other? I did know. Well, welcome to The Rest is Classified. I'm David McCloskey. And I'm Gordon Carrara.

And we are now in part two of this very special two-part, two-part series looking really in great detail at the founding, the founding story of the special relationship, the intelligence partnership between the US and the UK. And we are recording the story from a very special place. That's right. We are recording inside Bletchley Park in its auditorium. And with us here, we've got an audience of members of our declassified club. These were the people who were fast enough to snap up the tickets that were available. They've been having a little look around Bletchley Park in between us recording our episodes. They've had a chance to have a tour. We'll be doing more events like this in the future. So do sign up for

the club. The rest is classified.com if you want to be part of those. And we've been looking around the park and we've been looking a little bit at, you know, when we walked around David, at the place where it all began because our focus really isn't the whole of the Bletchley Park story. I mean, we might kind of go back to that in future episodes. It's too big too big. Too big. to do in two episodes. Too much. But we wanted to focus it on one particular interesting aspect of it, which is that US-UK intelligence partnership,

which was really born here, and which continues to this day, he says, question mark. Question mark. I'm Ron Burgundy. Yeah. It continues. It does. We just spoke a few days ago with a former MI6 chief,

who I think had some encouraging things to say. about the special relationship. But yes, it continues to this day. No need for the question mark on that, Gordon. Well, I suppose to set the scene of what we talked about last time before we get into it, we talked about these four Americans who had come to Bletchley Park in early 1941, probably the most secret establishment in the British military establishment at that point in the Second World War and where the Brits had made a very interesting breakthrough in cracking the Enigma Code, or a few versions of the Enigma Code that were used by the German military, the Luftwaffe, the SS to communicate operational information.

The Brits have made this breakthrough. The Americans don't know that the Brits have made this breakthrough, and the Americans are coming over with a purple machine, which is a reconstructed version of a Japanese cipher that the Brits don't know the Americans have broken. And so we have this very interesting exchange that's being set up and that happened right here at Bletchfield Park. This episode is brought to you by HP.

In intelligence work, it's rarely the obvious problem that causes failure. It's the overlooked detail or the flaw nobody quite solved. The kind of vulnerability, intelligence services look for. And running a business is the same, especially when you're building or growing a team, it's the risks you can't see or don't understand. HP designs technology, so devices, collaboration tools, and security work together as a single system,

helping teams keep everything running smoothly at home, in the office, and out in the field. The protection is built in, hardware-level security working quietly in the background, helping reduce risk without creating more work. With a team of business advisors, HP helps businesses of all sizes, find technology that fits their needs and budget. To see how HP helps businesses work securely and productively, visit HP.com forward slash

classified. The rest is classified listeners also benefit from 10% off HP business technology with code T-R-I-C-10. So we left with the four Americans led by Abram Sinkov, the head of this Sinkov mission, arriving Bletchley Park late February the 8th, 1941. The house is blacked out with curtains. And I'll say to set the kind of vibe of the house, the mansion, for those who have not seen pictures. To me, it looks a little bit like the Clue Mansion.

You played that board game. Well, you described it more like a kind of, like looking like something from an Agatha Christie murder mystery or something like that. Yeah, a large country house, I suppose. Late 19th century, I think it was built. not too old. And in that front room of the house is the office of Alastair Deniston, who's the head of Bletchley Park at the time. And he tells his 19-year-old assistant, Barbara Abernathy, I require you to come in with the sherry. This is, sherry is clearly very important in the

story. And you're not to tell anybody who's coming or what they're doing. And this is the American. So late at night, they walk in through the main doors of the house, pitch black, come to that hallway, then turn left into Deniston's study. And they're met there by a group of Britain's top code breakers. Deniston himself, John Tilton, who we heard about previously, who'd been escorting them possibly as they arrived. He's a very interesting character. We might come back to him. He'd actually started in the First World War breaking codes. And then it worked up on the border between then British Imperial India. and Russia breaking Russian codes in the 20s and 30s,

and then ends up coming to Bletchley Park. And the British code breakers stand in the semicircle, and they are introduced to the Americans. And finally, they get their sherry, which has been the source of much interest, I think, from you. Because you don't drink sherry. I don't drink sherry. No.

And I think it was whiskey was hard to come by. Yeah, that's what we were talking about last time. It must have been kind of a rationing thing. Yeah. Yeah. Yeah, and it's, supposing it's a really large cask, Barbara struggled slightly to pour it out, but she manages. And she says, I hadn't the faintest idea what they were doing here. I wasn't told, but it was very exciting, hushed voices, and I was told not to tell anybody about it.

So it is just a brief meeting there, because this is just really the start, what is going to be quite a long mission, which is going to go on for kind of a month and a half, effectively. And the Americans are not staying at Bletchley Park. They are staying at Shenli Park, which is a mansion, belonging actually to the president of the Anglo-Iranian oil company, which later becomes BP. Friend of the pod. Friend of the pod, yeah. Which is actually our very first shows were about the Anglo-Iranian oil company and its efforts inside Iran. But it's efforts, yeah.

It's efforts. But that's where they're saying. They've been put up in a pretty nice country house and they're looked after pretty well because it's got butlers. And the one detail that I think Sinkov, the leader of the mission remembers, though, is that one of the butlers looks down on him for failing to use a butter knife correctly. And this is one of many areas, Anglo-American tension. But they're here at Schengley Park, but they get chauffeur to Bletchley Park the next day. And that's the start of this working relationship. But it is cagey.

they are going to sit these Americans because they're specialists on different aspects of code breaking those four members of the American team and they're going to work with British counterparts and learn about what the Brits are doing during the day. They have lunch at a nearby pub. I don't think there was a cafe there then.

Then back to their manor house for dinner where they had to avoid discussing what they'd learned during the day. One point though is that particularly at the start, we talked about this last time, They are not being told everything. There is a decision not to tell them about the break into enigma, the work with the bombs that Alan Turing has developed, which are the machines to kind of cycle through possible breaks and enigma.

All of that is still being kept secret at the start. So they're being shown things, but not everything. It seems when you're in the accounts of that, the first few weeks of this visit, it's very unstructured in a lot of ways. They're kind of being led around to look at stuff. Yeah. And it almost seems like neither side is quite sure how to play it. How to play it. Yeah. How much is too much to share. But how also do you make this so that both sides can come out of it and say it's a success? Yeah. And nobody for the first few weeks has an answer to that question. Yeah. I think it's cagey. There's some socializing. Oh yeah. It is interesting how this is a very new experience for most Americans to be here. And a lot of the Brits have never met an American before. Yeah. Right. So both sides are kind of getting used to each other. The Americans are apparently taught rounders.

Yeah. Is this baseball, Gordon? Rounders is slightly different. And actually, I think that does at one point. Leads to some tension. It leads some tension. One of the tensions is they're having a game at one point. You score differently in rounders compared to baseball.

And so each are scoring it their way. And then they have a dispute about who's actually won the match. Because they each think they've scored more points than the other because of the different ways of scoring. But they, you know, I guess that's how you build relationships. They visit nightclubs? Yeah. So they go to London.

They go to London. They meet the chief of MI6. They go to the U.S. Embassy, where they annoy the people at the embassy because they can't say what they're doing there. Yeah. So they can't even reveal to the diplomats there. Well, that's also a classic tension in any, I mean, even today, right? If you go to an embassy or a station overseas and there might be some pieces of what you

or your team are doing that only the chief of station knows, or maybe they just know a little bit, it really grates on the local crew if you have people who come in, particularly technical people, from Washington or wherever, and show up and basically say, I can't tell you anything about what we're doing here. And we're having conversations with your counterparts. Yeah. They don't like that. And then you're right. They visit a nightclub. I mean, this is all very similar to your time here in London at the moment, isn't there? Cafe de Pari. Gin lunches. Gin lunches. Rounders. My clubs. Yeah.

We've got the rounders game afterwards. They go to the Café de Paris in central London. Your French has improved over the course of the podcast. To see a band, which is led by Ken Snake Hips Johnson, who was one of the leading West Indian musicians in Britain of the 1930s and 40s. And he was one of the only kind of successful big kind of black names in British music at the time. He came from British Guyana originally, and they play this West Indian dance music, which is very popular. So the code breakers go there.

The actor David Niven, very famous actor in British terms, is there the night they go there. And he's holding a tricycle race on the dance floor. Again, just like you last night, we were having a tricycle race on a nightclub dance floor, weren't we? I think. Is that a wartime thing? I don't know. Yeah. But what's, but this, again, is one of those details.

So they go there one night during this visit. The next night, a bomb hits the club. 34 people killed, including Snake Hips Johnson. And that is how he dies. And I think, again, a bit like their journey down the coast from Scotland towards Kent and then into Bletchley, where they come under fire by the Germans. This must be, for those Americans, to suddenly understand what the Blitz was, what it was to be bombed, what it was to see civilians die in that way in a nightclub.

must have had quite a powerful effect on them. And when you understand the bonds that are forged by this visit and by the joint cooperation at Lechester, I think it's actually understanding that trip to the nightclub and what happens the next day, which explains why such deep roots, I think, are put down in the relationship because of the things that they experience during that visit.

But even at that point, what is going on in, I think, Huts 6 and 8 and the work led by Turing? that's still not being shared. And regardless of what the Bletchley team might have wanted to share from the higher ups at this point, political leadership, Churchill, it's kind of... It shows something like, but still hold back, don't share. Yeah. And it's because of that fear that we talked about last time, the fear that the secret of the fact that they were making these breaks into Enigma could leak.

And therefore, then the Germans would change their codes, they'd upgrade their codes, they'd change the way they used the machine. and then you'd lose that break with huge consequences, you know, real life and death consequences, means there is that reluctance. And what you see is a tension within Bletchley Park. And Alastor Deniston, the boss, is one of the more reluctant ones, it seems, to open up, to share too much.

And of course, even within Britain, very few people are let into the secret of Bletchley Park. Yeah. Well, I think it's safe to say, though, that what breaks it open, this is so many examples in the special relationship, is just American generosity, isn't it? Taking the first step,

because it really is, though, the Americans who brought that purple machine to decrypt Japanese communications, primarily diplomatic communications. That's brought and essentially given, shown to the team here at Bletchley, without any, I mean, at that point, and even knowledge of what the Brits had done on Enigma, right?

So that first step is taken by the Americans, and it really pays off. Yeah, I think that is right. I mean, John Tilton, that British codebreaker, describes the gift of purple as a tremendous gesture. Somebody had to make the first step, he said, and the Americans made it. And I think it is interesting because the Americans, they don't use it as a bargaining chip. They don't go, well, we could give you something if you show us more. they basically go, here it is. And I think that actually is quite important because it does

make the Brits realize, okay, maybe we need to reciprocate. Maybe we need to do something in response. It actually seems like the exact inverse of structurally what happens today in pockets of the intelligence relationship. Because in 41, the Americans are the smaller partner, partner that kind of needs to demonstrate value. And so there's a willingness, I think maybe to take something that's really valuable and cool and share it to demonstrate from kind of the plucky smaller partner that there's that, hey, I can contribute. And if we pool resources, we both get more out of this than if we just do it alone. I think that there's a, you know, I'm thinking about exchanges with British counterparts on Humant. There's kind of a similar structural thing

going on today in the human relationship between MI6 and CIA, where, I think if the Brits collect really interesting, really good pieces of human, there can be a, you know, there's a strong desire to share it to say, look, this is something of value. And then it creates an impulse on the side, the bigger side, to share more. To open up. Yeah, exactly. And it is interesting because John Tilton, this actually very important figure in the relationship, goes to see the head of MI6 and make the case and say, look, they've opened up to us.

we should do the same as well. And the head of MI6 can see the point of that argument, but says only if Churchill himself signs off on it. Which gives you a sense of how important this technology is. Yeah. And how sensitive is and how bigger decision that is. And Churchill says you can tell them, but they have to sign a document with conditions about who they in turn can tell.

Yeah. Because they want to control that kind of flow. of information and make sure that word doesn't get out in Washington effectively about what's happened. So that's the deal. We will share it with them, but only if it's restricted to a tiny group of people who basically swear themselves to secrecy. So at that point, the decision is made.

And it is actually just before the Americans visit ends in March that they are told about the break into Enigma. They are shown the bombs, these machines, which you can see here, in Bletchley Park if you visit, you can see rebuilds of them, the ones that are used to kind of go through the various permutations. They're told and allowed to write down some, although maybe not all of the details of the techniques that the British are using to break and to attack things, even the more advanced naval enigma. They're not actually given any of the hardware, though, which is interesting, I think. The Americans have given the Purple Machine. The Brits don't give a bomb, for instance.

But the reason for that is simple is they don't have that many. And they're using them all and they need them all. You can't quite afford to just ham one over and lose the ability to use it day to day. It's a massive part of the value that they hope to get from the Americans, which will be the industrial capacity to build a lot more of these machines. And I think it is easy to forget now how remarkable this was because America is still not in the war. And yet they're sharing their deepest secret, which is what's happening at Bletchley Park. I mean, I do think it is, it's hard to get your head round. What a big step that is.

Yeah. Well, and especially in contrast to the slightly suspicious nature of the intelligence relationship in the 1930s. Yeah. I mean, it's really a sea change in the way the two countries are going to work together. Well, one American actually thinks that the Brits are also passing on the details. In their minds, they think, well, partly for help, but partly in continuity. And in their words, in case Britain goes under.

And then at least some capacity to break German codes and that knowledge will then be over the Atlantic. So it's almost a kind of fallback option as well, which shows you, I think, to some extent, the fears that are there. So the team, the four Americans go back in April. They return to the U.S. And, you know, if you put yourself in the mindset of an senior official inside the Army Signal Intelligence Service or inside naval intelligence, in some respects that Trip could look a bit like a failure because you've provided this really important piece of tech, the purple machine. You've gotten nothing in return.

And the, you know, what we'd call the bigot list or the list of people who are read into this information. Yeah, we should say bigot is. It's not people who are bigoted. It's not people who are bigoted. It's the slang for people who are read into a particular compartmental program. But it's a very small. Yeah.

Bigot list. So there'd be plenty of people in both of those services who would look at the at the Plutely Park time and say, Well, did you get out of that? This was a waste of time. Yeah. Which often happens after liaison trips. Does it? Yeah.

Come back and say, well, it was kind of a boondoggle. Now, I guess no one in 1941 would have thought it was great to come and sit in, you know, wartime Britain. Yeah. But still, you come back from a trip like this. You've given something valuable. And what do you have to show? And you can't tell people that you've come back. with something. So I think the gossip in Washington is like that was a failure, that mission. It's

really interesting. But it is the start of the relationship. Pearl Harbor dramatically changes things, obviously. It feels like without Pearl Harbor, obviously, the Bletchley visit is a footnote in in history. Yeah. Yeah, I guess so. I mean, it changes, I mean, it changes the thing, obviously, for the U.S. I think it brings the U.S. into the war also forces them to confront the need to overcome the rivalry between the Navy and the army and to get better at code breaking because they didn't have the advance warning for Pearl Harbor. And that's one of the problems is they realize the importance of trying to have that break into your opponent's codes.

And out of it, you get a division of labor. And I think that's, again, one of the legacies of Bletchley is that there's a clear division of labor in which the US is going to lead on breaking Japanese codes. and the UK is going to lead on breaking German codes. And they've each got a slight lead and expertise in that one, but they're also going to accept, with some people not being entirely happy about it, the idea that they'll leave the other half to someone else. There's some people who don't like that.

And I think, you know, and you feel they want to be doing everything. But actually, that division of labour is crucial. Yeah, the bureaucratic fragment. on the U.S. side is also interesting because you have, I think the Army, which is much more keen to work with the Brits, the Signals Intelligence Service, the Navy a little bit more reluctant. I think in part because the Navy wants to take the lead on breaking Enigma, right, and may not want to share credit with the Brits. And there's also, as we discussed last time, a lingering concern, I think that after the war, or even during it, these kind of advances could be used

for the Brits to spy on us. Yeah. Right. So that's all still there. It also, this kind of bureaucratic fragmentation division, I mean, it reminds me even of some of the features in the relationship today where the Brits, particularly SIS, MI6, will play off American services against each other. The FBI and the CIA.

Yes. Yes. There are, I mean, there are, there would be a senior American officials at the CIA and FBI who would say they feel closer and a deeper sense of trust with the Brits than they do with each other. Right. And so that, and the Brits, smart Brits, know this and use it to their advantage, right? I mean, there's this bit here, which is, I think, from an official NSA history, the NSA being the American co-breaking agency. It says British officials regarded negotiations with the Americans as a little like dealing with the former colonies after the American Revolution, disorganized and frustrating at times, but they could still play one off against each other to achieve objectives. Still happening today.

It's really interesting, isn't it? But yeah, there are these fears still over security. We talked about the importance of it. Tiltman manages, as this figure in the middle, to smooth over the same. some of the differences. I mean, Churchill famously calls the staff at Bletchley, the geese that laid the golden eggs, but never cackled.

And he will strike the names off of British officials who he thinks should not have access to the secret that is Bletchley Park in order to restrict it and make sure it doesn't leak out. And no actions will be taken

without a plausible cover story of why they could be taken so that it doesn't get traced back to it being based on intelligence from Bletchley Park. So there's great care being taken to do this. And the US effectively has to agree to those rules and those security strictures in order to be part of this arrangement. I thought the way that the Americans wind up being integrated into the Bletchley operation is very interesting. I mean, we should say we're talking about the story in the context of US-UK intelligence sharing. We shouldn't create the impression that

somehow there were thousands of Americans here. This was, I mean, I think at its height, thousand or so people, maybe only a few hundred Americans. Yeah. But they the the choice to integrate the Americans across the teams rather than sort of setting up some kind of American hut. Yeah. You know, also shows, I think, the depth of, of the partnership. In the same way today, you know, there have been times in the relationship between, you know, CIA and MI6 where we've integrated officers into each other's counterterrorism centers, right, rather than having your own cell. So it's, it's a measure. I think of trust in a partnership.

But then it is interesting because there's some of the cultural differences which become clear. We talked about that earlier with the rounders versus baseball issue. But there's interesting ones like the Americans tend to wear military uniform when they're at their headquarters, whereas Bletchley is emphatically not really a military organization where you're wearing uniform. And that was not the case at Bletchley. To make the point, one American liked telling people the story of two wounded persons,

personnel assigned to Bletchley to help out who, while they were convalescing, looked at the way people dressed and acted around Bletchley Park and believed they'd actually been sent to a mental institution. Because they go like, the way these people act, this is not normal. This is not within the military chain of command you'd have in an American organization. So there's definitely a kind of, there's an interesting kind of culture clash. Well, and I guess everybody seems exotic to everybody else, right? I mean, there's this great quote from Jean Howard, who was one of the women here at Bletchley.

She says, you know, they, the Americans were different animals. And the English they spoke had different meetings. They were fat. We were emaciated. They were smart. She points out 11 different sorts of uniform. We were almost in rags. They were rich.

We were poor. We were overworked and exhausted and having to teach people who barely knew where Europe was. That was the last straw. But then I do like, there's some great quotes. The quotes are really good. This is from a British official during the war, which is in the authorised history of GCHQ by John Ferris. The Brit tells Denniston, the head of Bletchley,

he said, you must have noticed yourself how very many childish qualities the American male has. His taste in women. Careful. Motor cars and drink. His demonstrative patriotism. his bullying assertion of his rights, his complete pig selfishness in public matters, and his incredible friendliness and generosity when he likes you.

Hell, anyone would think I don't like them, but perhaps it's as well that I'm fond of children. I mean, that's quite a quote. That is quite a quote. That's a very British quote too, isn't it? Sort of a politely slamming. Yeah, exactly. It is an interesting, ends up being a very interesting bunch, doesn't it? Because you have some mathematicians, you wind up with a lot of former bankers who were here, crunching numbers.

One of the guys who came over was Art Levinson. Yeah. Who has, it was very fond of baseball statistics. Not something I know that resonate with you, Gordon. Talks about the freezing outdoor toilets. I mean, is it, we saw walking around here today. I mean, this is a pretty Spartan setup. I mean, even in, you know, Turing's office, it's, it's pretty dingy, it's dark, shades pulled.

Yeah. You know, it's, this was not, you know, despite the fact that we're at a kind of a mansion, most of the people were not experiencing the sort of, uh, downtown abbey style living. No, right? Definitely not. And I think, um, Art Levinson says he can always remember the freezing outdoor toilets, as well as working with one colleague with a refined Cambridge accent and another from Glasgow. While he was made to feel very welcome, he never had a clue as to what either was saying,

which I love. But of course, the other thing we should mention is for some reason the Americans do seem exotic, especially to some of the women at Bletchley. And Barbara Abernethy, Deniston's assistant. Who serves the sherry. He ends up marrying one of the Americans. She's one of quite a few who ends up marrying these exotic Americans with their childish qualities. Very childish qualities. seems strangely attractive to some British women. I don't quite understand that. But anyway, there you go. But, yeah, Art Levinson is a good example of one of those co-breakers who comes over

and who starts seeing the value of what the Bletchley decrypts can offer. And, I mean, we're not going to get into the whole detail of how Bletchley does shape the victory that comes in the Second World War. But there are some important moments which he will personally witness. You know, for instance, you know, he can. can remember why the German commander Romel is kind of raging about why every one of his supply ships is being sunk by a British destroyer. And Romel is saying it can't be coincidence. It's the damn machine. And Romel has clearly worked. Was that message then typed into the machine? Yeah,

exactly. And they've intercepted it. And so they hold their breath because they're thinking, Rommels maybe worked out that enigma is vulnerable. And that's why all these supply ships are being. But, but it's so interesting that the Germans, it's almost too much to contemplate the idea that enigma is breakable because the implications of that are so awful for the Germans that they'd have to change so much that they can't quite get their heads around it even though as we can see romill and some others occasionally think maybe maybe that's why these things are happening i guess you can you can understand the inability perhaps to even come to terms with the fact that enigma might have been cracked because

I mean, prior to the war, I believe, even, I mean, senior British cryptographers were saying it's unbreakable, right? It's an interesting question, though, is why did the Germans, I mean, is it fundamentally that assumption that it's unbreakable, that the Germans don't set up their own version of Bletchley? Yeah. Because you don't have a German Bletchley. No, I mean, they have some good individual co-breakers. And actually, in North Africa, for instance, there's a very good co-breaking team assigned to Romola and to others. But the problem is they never join forces. I think they have separate teams, but they don't have that integrated system that you have at Bletchley, where it's all brought together, all the different skill sets and all the different understandings.

And I think that is quite unique at Bletchley. And I think one of the things that America then offers is industrial muscle, really, to take some of these breaks into. Enigma and other systems and build on them and actually use American capacity to do more with it. And I think that's a key thing that America brings to the party, really. Turing was a bit skeptical of the Americans' contributions on the cryptography, wasn't it? And he has this great line where he says, I am persuaded that one cannot very well trust these people, meaning Americans, where a matter of judgment in cryptography. is concerned. I think we can make quite a lot of use of their machinery.

Yeah. That's what they think. Yeah. Despite the partnership, there's this very arrogant undertone, maybe even overtone, to some of the senior Brits here in terms of what the Americans really bring to the table. Yeah. But they do bring this industrial muscle to the table because one of the problems for Britain is producing the bomb machines, the ones you can see here at Letchley. And Turing had designed them, but it's the US which builds them on an industrial level. And they use the National Cash Register Company, the NCR in Dayton, Ohio, which can build these machines at a pace that Britain simply cannot. And they'll run some of them in the US. They're also running bombs here at Lechley, also a place called Eastcott.

And the messages are being passed back and forth over the Atlantic for the American machines to break as well. So you start to see that as well as the individual code breakers that the Americas can send over, they are actually providing something quite important in that relationship. We're not going to go into incredible depth here on Turing and the effort to, I mean, essentially build what becomes the modern computer. Yeah. I mean, that's a whole kind of separate story. But, I mean, it is a really interesting piece of what's going on here at Bletchley. And, I mean, we talked about how, you know, Enigma is really being used by the kind of operational level. Yeah.

Of the German military and Navy. But there's a level above that. Yeah. Which the Nazi High Command is using to communicate with essentially its army groups out in the field that becomes the focal point for a lot of Turin's efforts. Yeah. And that more advanced code that they're using at kind of strategic level is the one. is the one that Colossus, the world's first semi-programmable computer, which is built here at Letchley Park, is going to be designed to crack.

I mean, it's an amazing story. And again, I think we should delve into it another time. There's a post office engineer Tommy Flowers who plays a really important role in this in designing and building the system. And that will offer more amazing insights. And again, you know, Art Levinson, this American, can remember some of the messages that he will get from this break into the German high-level system. And he can remember decoding a 70,000 character account by Romel

of his inspection of defenses along Normandy before D-Day. Imagine why that would have some value. Yeah, if you're planning to invade, knowing where the defenses are because you've intercepted the message mapping them out is brilliant. And it's the detail, because it locates a German panzer division just close to where the U.S.

was going to drop the 101st airborne. And Levinson says, you know, they would have been torn to pieces. So they moved it based on the intelligence. That, I'm sure, saved lots of young men in the 101st airborne. So you can see with something like D-Day specifically, as well as other things like the Battle of the Atlantic, just how much difference Bletchley Park is going to make. I guess a lot of the claims around the impact that Bletchley has had center on, well, by how many months or years that it shortened the duration of the war. I mean, I think some of them say, oh, it's 18 months, maybe two years. I mean, what's your sense after looking at it of kind of the impact on the conflict? Or is that even a useful measure? I don't think it's a useful measure.

I think this idea you can say, well, it would have been two years longer or 18 months longer without Bletchley. I mean, I don't think it kind of works like that. It's so integrated with the operational activity, whether it's in North Africa, whether it's in, you know, around D-Day, whether it's around battle at the Atlantic and also all the things that are happening in the Pacific. I don't think you can kind of separate it out and say if it wasn't there, this would be the implications. All you can really say is it plays a really significant role in helping win the war. And as, yeah, as Levinson said, I mean, some of those individual almost tactical operational decisions of saying, well, let's not, let's not position 101st airborne here, let's position them here. Or if you think about eventually

when, when, you know, naval enigma is broken and you have a sense of where U-Boats actually, actually are and you can reroute shipping lines, you know, it's probably tens of hundreds of thousands of lives saved purely by the efforts here at Bletchley. And I mean, who knows, no, counterfactuals or counterfactuals, but who knows how those really dark years of 1941 and 42 go in terms of just being able to resupply Britain if you don't have it. Yeah. So it's, yeah, I agree that the time duration feels, a bit like a useless measure, but it very obviously had a massive impact in saving lives and in, you know, opening up really important supply chains.

So there, I think with the war coming to an end, Bletchie's legacy isn't over. So let's take a break and look at what it means for the special relationship afterwards. Hello, it's Gordon here, and I'm with Tabby from Gollhanger's new show. the book club. We're not here, are we happy to announce the new James Bond, but we are here to discuss a book that you've just covered, which may have inspired the character. That is correct, Gordon. So this week, Dominic Sambrick and I have been discussing John Buckens, the 39 steps. And now this is undoubtedly one of the greatest British spy thrillers of the 20th century. And it's a real trailblazer for that genre, so the birth of Bond. Absolutely. Secret squirrels will know that here on Classified

we're a big fan of historical intrigue. And in the 39 steps, we meet the dashing Richard Hane, based on David McCloskey, as he races to prove his innocence, whilst inadvertently foiling a German plot to spark the First World War. Yeah, and it's a plot that bears an uncanny resemblance to the assassination of the figure that's sparked the First World War in real life,

so that's intriguing. And Hane's journey takes us from the hustle and bustle of London to the scum. Scottish Highlands in this game of cat and mouse and espionage that starts to unfold around our main character. So to listen to the 39 steps search for the book club, wherever you get your podcast and follow along so you don't miss out on more of their upcoming thrillers. Yeah, including Goldfinger and Tinker Taylor Soldier Spy. So lots to look forward to. Thank you so much for listening. Thank you for having me, Gordon. Goodbye. No problem, Tabby. Bye. Well, welcome back. The war is

over, but what happens to Bletchley Park, Gordon? This is, it's not a, there's no inked agreement at this point to suggest this kind of cooperation on signals, intelligence, and cryptography is going to continue. And yet, it does. It does. Yeah. And it's interesting because there was no guarantee it would continue. During the war, they had started to write up agreements to regulate the relationship. And there's something called the, the. British USA agreement, Broussa, which is... Brouser is a good name. Brouser is a good name.

May 1943. And essentially that's about regulating how Ultra, which is the material created from decrypting enigma, how it's passed around, how it's produced, and essentially making sure that it's not compromised by anything. But yes, I mean, the question is, at the end of the war, what's going to happen to To co-breakers and to this world, because if you look after previous conflicts, there's this pattern where the budgets get cut, you know, the code breakers get disbanded because it's seen as a kind of wartime necessity. And they go, everyone goes there separate ways and people go back to civilian life and to other normal activities. There are some who want to cut it off on the American side because they think, well, you know, we want to do this ourselves.

We don't really want to work with the Brits. But I think what's so important is the fact that they have worked so closely has shown the value of cooperation during the war. I think that's the thing is that both on the individual level of those intergrees, the people who've been integrated into Bletchley, they can see the value that it's broad. But also at the very top level, politically, the leadership, the military leadership, the political leadership,

they can see the value of joint co-co-co-executive. breaking. Well, and it's also, I mean, frankly, benefited by the fact that at that point in time, beginning of the Cold War, Britain's global rule beginning, or I mean, had been shrinking, but really contracting the American one growing. And yet at the same time, there's such a convergence of geopolitical interest with the Cold War happening, right, in Europe, around the world, that the logic of disbanding this kind of arrangement is really flawed. Because, I mean, essentially, and I think it's the same logic that it governs a lot of the intelligence partnership today is if both countries bring 10 units and share, that means

both countries have 20 units, right? And fundamentally, that math just holds up if you have a real convergence of national interest at the geopolitical level. which you've got because I guess it is so crucial that as soon as the war is ending, the Cold War is starting. There's even a bit of crossover where they're starting to think and spy on the Soviets, even though they're allies at the end of the war. But it's certainly clear by the end of it that a new conflict is coming. And on September the 12th, 1945, the US chiefs of staff tell President Truman that cooperation with the Brits was essential to American national security given the

disturbed conditions of the world. And what they're worried about is actually another Pearl Harbor. It's another surprise attack. It's being taken by surprise, perhaps even by a nuclear surprise, by the Soviet Union, who are developing the bomb, although they don't have it yet. And the Brits, again, have something because they've been working against the Russians longer than the Americans. Yeah.

Because the Brits were working against the Russians in the 20s and 30s and a bit in World War II. Whereas the Americans have never really focused on the Russians. And so for that reason as well, the Americans are thinking, well, these guys have got something that is potentially quite useful to us in this new world. Therefore, there's a value in maintaining a relationship. And you can even see the kind of impulse reflected in the way that the OSS and then what will become very young CIA, the tradecraft, it really comes from MI6. A lot of those OSS officers served in the war are kind of tutored in many ways by their British

counterparts here in London. And obviously there's a deep intelligence sharing relationship that begins right away with the sort of Nesson, CIA. So the alliance, though, gets deeper in 46. Yeah. That's when you get the Yakuza, as it's known, which is the UK-USA, which is a formal agreement, not a national treaty. It's interesting because it's deniable.

So it's a secret agreement between the two sides. It's non-binding. So both sides can kind of pull out of it when they want. It's actually kept secret until 2010. I mean, everyone knows it exists. But the actual document itself is kept secret until then. And it solidifies this relationship which had come through Bletchley Park, through that visit in 1941, into a marriage, effectively, between the two sides.

I mean, that's what it really feels like in terms of the commitment that they promise each other. And one of the stipulations is to promise honesty and openness with each other, which obviously we do all the time, right? This is really important. They agree to divide up the world in terms of the coverage. And in particular, when you're talking about signals intelligence, that's hugely valuable.

Because in the human intelligence world, it matters too, because where certain countries have consulates and embassies and others may not. It really does matter. Geography matters. But with signals intelligence in particular, having a listing post, having geographic coverage is really, really important. So that's a significant piece of it as well. They promise fidelity. So there would be no deals or sharing with any other third parties unless both parties agreed that that would happen.

And secrecy. So, you know, again, we have that the fear, particularly from the British side, that there would be a repeat of the Black Chamber experience. having this whole thing leaked in the aftermath, these agreements really sew that up so that doesn't happen. Yeah, that's right. And the secrecy extends to the fact that no one who knows the secrets of this joint co-breaking work could be put in any position where they could be captured or subject to interrogations. And that's actually one of the stipulations to try and maintain that secrecy. They also agree not to spy on each other, which may be something we should come back to because, you know, that's, that was the mistrust that came out of the 30s when they knew

they'd been spying on each other. But they're going to agree not to spy on each other. And they prepare for the long term and even for the worse. I mean, that's when you start to see the institutions, which are the modern institutions forming because Bletchley is going to close down. It's going to move to the outskirts of London briefly. But then they'll move code breaking to Cheltenham. And it's a location chosen to be away from London precisely. A bit like Bletchley was chosen to be away from London because they're worried it could be the target for nuclear weapons now or for bombs. And so Cheltenham is a bit out of the way.

Some actually think that they should go all the way to Canada. And they should move. That was a bit of a mistake. But they decide on Cheltenham, which is a bit closer than Canada. And they're going to use some of the kind of cabling and some of the infrastructure, which is there because there's good communication. lines. And then meanwhile in the US, you're also going to get the evolution of code breaking into more formal organizations and institutions. Which I think really the impetus of Pearl Harbor

in the sense that the failure of the services to cooperate and collaborate partially led to that disaster leads to a lot more centralization of the US codebreaking and signals intelligence apparatus until finally in 52, you get the creation of the modern NSA underneath the military. Yeah, and that's still one of the differences, isn't it? Is that whereas GCHQ is a civilian under the foreign office, NSA is a military organization, which again mirrors some of those kind of Second World War differences. And then you also, it was the Yakuza deal originally, but then Canada, Australia and New Zealand are brought into it, and you get what are now called the Five Eyes.

It's a little bit of tension about whether the Americans can talk to the Canadians direct or whether they have to go through Britain. But eventually it's worked out that this is going to be the best way of organizing themselves. Still little tensions, though. It's kind of interesting. I find some of this. For instance, Britain actually offers some of its colossus, these computers, early computers, to the Americans. The Americans turn it down.

And the Brits realize one of the reasons they're turning it down is because they want to build them themselves. themselves. You know, they don't want to be dependent. Yeah. And you can understand that. There's this constant sense of the power shifting slightly to the American side. And America constantly thinking, well, it's useful to have this relationship with the Brits. But ultimately, we want to be able to do it ourselves and build our own machines. And the balance between realizing that there's a benefit in working together, but also not being too dependent, is something which is there. But on the whole, the realization will be two heads are better than one or five heads are better than one.

Well, I also think the closer two sides get and the more information sharing there is between the two of them, because you're seeing the same stuff, you start to see the world in the same way too. So the relationship can be, you know, cemented on the basis of a shared sense of mutual threat. and that could be, you know, in theory, that could be a very transactional thing when that threat's gone, you know, you part ways. I guess with the geopolitically with the Cold War happening, that doesn't happen. And then you end up with this, you know, I think it really an information system inside this five eyes that in and of itself creates the conditions for more trust because you have a shared way, a shared language about what's going on in the world because you're looking at all the same information. You're looking at the same intercepts. you're looking at most of the same human intelligence.

And I think that is really a lot of the glue that holds this thing together. It also goes back to the idea that GCHQ is smaller than the NSA. So Britain is now, you know, goes from being the larger partner to the smaller partner, but there is still value in having a different perspective as well on something like code breaking. You know, right from the start where we talked about the polls bringing a different way of looking at the problem of enigma, you get the same thing, I think, with Co-breaking, where, you know, another partner allows you to see a problem in a different way. They also might have different geography, which gives you access to collecting signals, whether it's from undersea cables or radio, which you wouldn't get another way. And so the benefits there become pretty clear.

And they're all based, I think, on that, you know, that way of working at Bletchley in which you divide up the world for targets, you work together. And it's so interesting because the staff are still seconded back and forth. And John Tiltman, who was one of the people we talked about there, who'd been there in Bletchley, he to me is a really interesting example about that because he, after the war, continues at GCHQ. He then retires from GCHQ in the 60s. And then he moves to the United States and works as a contractor for NSA. And he works at NSA until 1980. And I just find it extraordinary because this is a guy who I think is born in the 1890s.

and he is breaking codes in World War I. He's breaking codes on the border between India and the Russia in the 1920s and the Soviet Union. And he's there in World War II up, actually. And then he's there in the computer age in the NSA, you know, through the 70s as a Brit, who suddenly seconded to the NSA. And you kind of go, that's an amazing example about how close those relationships are. he ends up inducted into the NSA's call of honor. I don't know how many other kind of foreign nationals are in there, but it can't be that many.

And John Tilman's one of them. And Anne Keist Butler, who's head of GCHQ, right now and was here at Bletchley, I think just a few months ago for a lecture in the very room where we're recording today. She said that the leap of trust, this leap of trust, meaning Bletchley, paved the way for the strongest intelligence alliance in the world. here at Bletchley Park, American and British codebreakers work side by side, and that continues to this very day. In GCHQ's Cheltenham, Manchester, and London hubs, and an NSA offices from Fort Meade to San Antonio. They still have integries, as they're called, I mean, working together in each other's

organization. So, and you got, apparently, she must have leaked that there's an NSA hub in San Antonio, Texas. I didn't know where I'm from. Yeah. She's just declared it. She's just declared it. So like a yardly style reveal for man.

But also, it's funny, someone, I was talking to someone who used to work at GCHQ for many years. And they just gave me a small example of how that integration of people still matters. And they said, if you're at the car park for GCHQ in Cheltenham, as some of you may have, may not have been, you swipe in past barriers to get into the car park. And some of them have a swipe machine on the left as well as the right. and that's to ensure that U.S. personnel driving left-hand cars can get into work without having to get out of their car and walk. So they're even shipping their cars over. It's an example of the fact that they're built for joint working, which came out of the integration, which was here.

And it has survived in an interesting way to the point where I think after 9-11 there were worries of what would happen if the NSA was taken out by a terrorist attack or by a nuclear weapon or something like. And the idea was that GCHQ in the UK would take over the US Signals Intelligence. You know, it would become the headquarters and the base for it. Which is crazy. Which is crazy when you think about it? There is no other... Is there another intelligence partnership in the world where one side would say, if my signals intelligence capability is destroyed, I will actually create a backup plan so that

it could be transferred to a foreign country. Yeah. And it's insane. It is insane. Although I like the British parallel. which was that their worry, in the US they were worried about like a major, you know, terrorist attack or something like that. In the UK, they were worried about floods near Cheltenham in 2007. And they were so worried about flooding near Cheltenham that might take GCHQ offline that in that case, then the Americans...

Move it to the NSA. So there it's terrorism with us. It's floods, you know. That's the difference. It's always more dramatic on the American side. You've always got to have the drama, haven't you? You can't let go of that. It's our childish ways. I also think, I mean, the signals intelligence piece in particular, because the systems and the installations are so capital intensive,

it creates a logic behind that integration that I don't think you see in the same way on the human intelligence side, where it's still a bit more transactional. Yeah. Right, because you can, it's easier to turn off the dials of one particular stream of human intelligence reporting or just to not share it. Whereas if you're sharing literally the systems and the infrastructure on the signals intelligence side and collecting things, it's a bit harder to sequester one piece of it or one stream of it as British or American. Yeah, you can't imagine the CIA handing over control of its operations to MI6, can you? No.

That's a little bit harder. Yeah, it's a little bit harder to imagine. That human stuff still is, the signals, how the. the signals intelligence kind of platforms are developed is obviously extremely sensitive, but both sides still kind of jealously guard in some cases the identity of their human sources, I think more so than the installations and systems and platforms that are used for signals intelligence. Yeah. And I think it is that point about trust and integration, which are the defining characteristics of that signals intelligence relationship. And it really did just come out of those

four people turning up abletchly in February 1941. I think that's what's so interesting is that it's not often you can date so clearly the beginning of a relationship which where are we now, 85 years on, is still going. It's still going. It's had its hiccups recently.

It's had its hiccups recently, but it's still going. Yeah. And I think it's a testament to just how much trust has been built up and how much that trust has been turned into to really deep institutional connections at all levels, really. You know, this isn't for people going somewhere to meet with a few people and then come back and that could kind of be an ad hoc thing. Now it's just thousands of relationships every day and an integration of services that I think

makes it even if we're in a period of, what was the line from referring to the early Cold War is a disturbed period of politics? Yeah, we're sort of, it feels like that's what we have today. Even if those disturbances sometimes ruffle the politics at a high level between London and Washington, this infrastructure is really hard to unwind, even if someone wanted to purposely. It would be very hard to do that. Very hard. Very costly.

So yes, so it's lasted 85 years. Will it last another 85? Well, we could come back here and find out. Our successors maybe. Our successors maybe. I don't sure we'll be around in 85 years to find out. But that feels like a good place to leave the story of Bletchley Park. We hope you've enjoyed it.

A big thank you to those who've joined us in place. And a big thank you also to Bletchley Park. To the staff and team. It is a wonderful place to visit, a great place to spend a day and to really understand what goes into co-breaking, the genius of it, but also the hard work. And all those people who dedicated so much effort in absolute secrecy. for those wartime years, which made a huge difference

and laid the foundations for where we are today. Yeah. And just a reminder, if you have not joined the Declassified Club, as all of these wonderful, wise people in this room

have already decided to do so, go and join the club at the rest is classified.com. You can get access to join us for events like this, early listening to our series and a whole bunch of other goodies. But we thank you,

and we'll see you next time. See you next time. Hey, guys. This Anthony Scaramucci for the rest is podcast. politics, U.S. Katty K and I want to tell you about our North American tour in October. Donald Trump is rewriting the history of the United States. From trade wars to immigration crackdowns to global conflicts, we are here to make sense of all of it. You know, we're in an era

defined by depolarization and American institutions are breaking under Donald Trump. Katty and I will be live on stage, breaking down what's really happening, sharing insight, perspectives and answering your questions. This October we're heading to Toronto, Boston, New York, Washington, D.C., a host of other American cities to get into all of the political action. We would love to see you there. Come and join us. So head to the rest is politics us.com to get your tickets and come see us live.