182. The Imitation Game: The Codebreakers Who Defeated Hitler (Ep 2)

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: ⁠⁠⁠⁠⁠[email protected]⁠⁠⁠ 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

Speaker names marked ? are inferred from speaking time and the show’s known hosts — they are not voice-verified.

• 0:03David McCloskey?

  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 therestisclassified.com.

• 0:25David McCloskey?

  A secret mission to Bletchley Park, but can the Brits and Americans really trust each other?

• 0:30Gordon Corera?

  I don't know.

• 0:31David McCloskey?

  Well, welcome to The Rest Is Classified. I'm David McClosky.

• 0:34Gordon Corera?

  And I'm Gordon Corera.

• 0:35David McCloskey?

  And we are now in part two of this very special 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 this story from a very special place.

• 0:55Gordon Corera?

  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 at therestisclassified.com if you want to be part of those. And yeah, 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.

• 1:39David McCloskey?

  It's too big to do in two episodes, isn't it?

• 1:42Gordon Corera?

  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?

• 1:56David McCloskey?

  Question mark. Question mark. I'm Ron Burgundy?

• 1:58Gordon Corera?

  Yeah.

• 2:01David McCloskey?

  It continues.

• 2:02Gordon Corera?

  It does.

• 2:02David McCloskey?

  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

• 2:46David McCloskey?

  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 Bletchley Park.

• 3:20Gordon Corera?

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• 3:22David McCloskey?

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• 3:34Gordon Corera?

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• 4:10David McCloskey?

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• 4:28Gordon Corera?

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• 5:10Gordon Corera?

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• 6:24Gordon Corera?

  So we left with the four Americans, led by Abram Sinkov, the head of this Sinkov mission, arriving Bletchley Park late February 8, 1941. The house is blacked out with curtains.

• 6:38David McCloskey?

  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 kind of, it looks a little bit like the Clue Mansion. You played that board game?

• 6:48Gordon Corera?

  Well, you describe it more like a kind of, like, looking like something from an Agatha Christie murder mystery, or something like that.

• 6:54David McCloskey?

  Yeah, a large country house, I suppose.

• 6:57Gordon Corera?

  Late 19th century, I think it was built. So not too old. And in that front room of the house is the office of Alistair 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 Americans. 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 Tiltman, who we heard about previously,

• 7:41Gordon Corera?

  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 had 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 a semicircle, and they are introduced to the Americans. And they're finally, they get their sherry, which has been the source of much interest, I think, from you, because you don't drink sherry.

• 8:19David McCloskey?

  I don't drink sherry, no.

• 8:20Gordon Corera?

  And I think it was whiskey was hard to come by.

• 8:22David McCloskey?

  Yeah, that's what we were talking about last time. It must have been kind of a rationing thing.

• 8:26Gordon Corera?

  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 of what is going to be quite a long mission, which is going to go on for kind of a month and a half, effectively.

• 8:52David McCloskey?

  And the Americans are not staying at Bletchley Park.

• 8:55Gordon Corera?

  They are staying at Shenley Park, which is a mansion belonging, actually, to the president of the Anglo-Iranian Oil Company, which later becomes BP.

• 9:04David McCloskey?

  Friend of the pod.

• 9:05Gordon Corera?

  Friend of the pod, yeah. Which is actually, our very first shows were about the Anglo-Iranian Oil Company and its efforts inside Iran.

• 9:14David McCloskey?

  But it's efforts, yeah.

• 9:15Gordon Corera?

  It's efforts. But that's where they're saying, so 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...

• 9:41Gordon Corera?

  They're here at the at Shendley Park, but they get chauffeured 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,

• 10:22Gordon Corera?

  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 the machines to kind of cycle through possible breaks in Enigma. All of that is still being kept secret at the start. So they're being shown things, but not everything.

• 10:41David McCloskey?

  It seems when you read 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.

• 10:52Gordon Corera?

  Yeah.

• 10:53David McCloskey?

  And it almost seems like neither side is quite sure.

• 10:57Gordon Corera?

  How to play.

• 10:57David McCloskey?

  How to play. 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?

• 11:05Gordon Corera?

  Yeah.

• 11:06David McCloskey?

  And nobody for the first few weeks has an answer to that question.

• 11:10Gordon Corera?

  Yeah, I think it's cagey.

• 11:11David McCloskey?

  There's some socializing.

• 11:12Gordon Corera?

  Oh, yeah.

• 11:12David McCloskey?

  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.

• 11:20Gordon Corera?

  Yeah.

• 11:20David McCloskey?

  Right? So both sides are kind of getting getting used to each other. The Americans are apparently taught rounders.

• 11:25Gordon Corera?

  Yeah.

• 11:26David McCloskey?

  What is this baseball, Gordon?

• 11:27Gordon Corera?

  It's rounders is slightly different. And actually, I think that does at one point.

• 11:32David McCloskey?

  Leads to some tension, doesn't it?

• 11:33Gordon Corera?

  It leads to 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.

• 11:55David McCloskey?

  They visit nightclubs?

• 11:56Gordon Corera?

  Uh, yeah. So they go to London. They go to London. They meet the chief of MI6. They go to the US Embassy, where they annoy the people at the embassy because they can't say what they're doing there.

• 12:07David McCloskey?

  Yeah.

• 12:07Gordon Corera?

  So they can't even reveal to the diplomats there.

• 12:09David McCloskey?

  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 can't, 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.

• 12:36Gordon Corera?

  Yeah.

• 12:36David McCloskey?

  And we're having conversations with your counterparts.

• 12:39Gordon Corera?

  Yeah.

• 12:39David McCloskey?

  You know, they don't like that.

• 12:41Gordon Corera?

  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 it? Cafe de Paris.

• 12:47David McCloskey?

  Gin lunches, rounders, nightclubs.

• 12:50Gordon Corera?

  Yeah, we've got the rounders game afterwards. They go to the Cafe de Paris in central London.

• 12:56David McCloskey?

  Your French has improved over the course of the podcast, Gordon.

• 12:59Gordon Corera?

  To see a band, which is led by Ken Snakehips 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 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, we were having a tricycle race on a nightclub dance floor, weren't we, I think?

• 13:42David McCloskey?

  Is that, was that a wartime thing? Or what was?

• 13:44Gordon Corera?

  Yeah. But, 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. Thirty four people killed, including Snakehips 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, you know, civilians die in that way in a nightclub, must have had quite a powerful effect on them. And when you understand the bombs that are forged by this visit and by the joint cooperation at Bletchley, I think it's actually understanding that trip

• 14:29Gordon Corera?

  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.

• 14:41David McCloskey?

  But even at that point, what is going on in, I think, Huts six and eight and the work led by Turing?

• 14:48Gordon Corera?

  Nothing.

• 14:48David McCloskey?

  That's still not being shared.

• 14:50Gordon Corera?

  No.

• 14:51David McCloskey?

  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 show some like, but still hold back. Don't share.

• 15:01Gordon Corera?

  Yeah. And, and it's because of that fear that we talked about last time, the fear that the secret of the, 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 use the machines. And then you'd lose that break with huge consequences, you know, real, real life and death consequences. It means there is that reluctance. And what you see is a tension within Bletchley Park. And Alistair Deniston, the boss, is one of the more reluctant ones, it seems, to, to open up, to share too much. And of course, even within Britain, very few people are let into the secret of Bletchley Park.

• 15:43David McCloskey?

  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, that purple machine.

• 16:00Gordon Corera?

  Yeah.

• 16:01David McCloskey?

  To decrypt Japanese communications, primarily diplomatic communications. That's brought and, and essentially given, shown to the team here at Bletchley without any, I mean, at that point, even knowledge of what the Brits had done on, on Enigma, right? So it's that that first step is, is taken by the Americans and it really, it really pays off.

• 16:23Gordon Corera?

  Yeah, I think that is right. I mean, John Tiltman, that British code breaker, 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, 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.

• 16:55David McCloskey?

  It actually seems like the exact inverse of structurally what happens today in, 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, with British counterparts on, on human. There's kind of a similar structural thing going on today in, in the human relationship

• 17:40David McCloskey?

  between MI6 and CIA, where I think if they're, if, 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.

• 17:59Gordon Corera?

  To open up.

• 18:00David McCloskey?

  Yeah, exactly.

• 18:01Gordon Corera?

  And it is interesting because John Tiltman, 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.

• 18:24David McCloskey?

  Which gives you a sense of how important this technology is. Yeah.

• 18:27Gordon Corera?

  And how, how sensitive is, and how big a 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.

• 18:40David McCloskey?

  Yeah.

• 18:40Gordon Corera?

  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'll, 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

• 19:24Gordon Corera?

  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, they can't quite afford to just hand one over and lose the ability to use it day to day.

• 19:52David McCloskey?

  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.

• 19:59Gordon Corera?

  And I think it is easy to forget now how remarkable this was, because America's 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 around what a big step that is.

• 20:16David McCloskey?

  Yeah, well, and especially in contrast to the slightly suspicious nature of the intelligence relationship in the 1930s.

• 20:25Gordon Corera?

  Yeah.

• 20:25David McCloskey?

  I mean, it's really a sea change in the way the two countries are going to work together.

• 20:29Gordon Corera?

  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, you know, to some extent, the fears that are there.

• 20:54David McCloskey?

  So the team, the four Americans, go back in April. They return to the US. And, you know, if you put yourself in the mindset of an American, you know, a senior official inside the Army Signal Intelligence Service or inside naval intelligence, in some respects, the trip could look a bit like a failure, because you've provided this really important piece of tech, the Purple Machine. You've got 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.

• 21:24Gordon Corera?

  Yeah, we should say bigot list isn't people who are bigoted.

• 21:26David McCloskey?

  It's not people who are bigoted, sorry. Yeah, it's, it's, it's the slang for people who are read into a particular compartmented programme. But it's a very small bigot list. So there'd be plenty of people in both of those services who would look at the, at the Bletchley Park time and say.

• 21:42Gordon Corera?

  What did you get out of that?

• 21:43David McCloskey?

  This was a waste of time.

• 21:45Gordon Corera?

  Yeah.

• 21:45David McCloskey?

  Which often happens after liaison trips, by the way.

• 21:48Gordon Corera?

  Does it?

• 21:48David McCloskey?

  Yeah. Come back and say, oh, 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. But still, you come back from a trip like this, you've given something valuable, and what do you have to show?

• 22:05Gordon Corera?

  And you can't tell people 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.

• 22:14David McCloskey?

  Yeah. Pearl Harbor dramatically changes things, obviously. It feels like without Pearl Harbor, obviously, the Bletchley visit is a footnote in, in history.

• 22:25Gordon Corera?

  Yeah, yeah, I guess so. I mean, and it changes, I mean, it changes things, obviously, for the US. I think it brings the US 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 advanced warning for Pearl Harbor. And that's one of the problems, is they realise the importance of trying to have that break into your opponent's codes. And out of it, you get a division of labour. And I think that's, again, one of the legacies of Bletchley, is that there's a clear division of labour in which the US is going to lead on breaking Japanese codes, and the UK is going to lead on breaking German codes.

• 23:10Gordon Corera?

  And, and they've each got, 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. You know, there's some people who don't like that, and I think, you know, and who feel they want to be doing everything. But actually, that division of labour is crucial.

• 23:33David McCloskey?

  Yeah, the bureaucratic fragmentation on the US 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, for the Brits to spy on us.

• 24:08Gordon Corera?

  Yeah.

• 24:08David McCloskey?

  Right? So that's, that's all still there. It also, this kind of bureaucratic fragmentation division, I mean, it reminds me even of some of the, the features in the relationship today, where the Brits, particularly SIS, MI6, will play off American services against each other.

• 24:29Gordon Corera?

  No.

• 24:30David McCloskey?

  The FBI and the CIA.

• 24:31Gordon Corera?

  Really?

• 24:31David McCloskey?

  Yes, yes. There are, I mean, there are, there would be 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?

• 24:52Gordon Corera?

  I mean, there's this bit here, which is, I think, from an official NSA history, the NSA being the American Code Breaking Agency. It says, "British officials regarded negotiations with the Americans as a little like dealing with the former colonies after the American Revolution. Disorganised and frustrating at times, but they could still play one off against each other to achieve objectives."

• 25:14David McCloskey?

  Still happening today.

• 25:16Gordon Corera?

  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 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, 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.

• 26:01Gordon Corera?

  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.

• 26:12David McCloskey?

  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, right? This was, I mean, I think at its height, 10,000 or so people, maybe only a few hundred Americans.

• 26:32Gordon Corera?

  Yeah.

• 26:32David McCloskey?

  But they, the, the choice to integrate the Americans across the teams, rather than sort of setting up some kind of American hut.

• 26:40Gordon Corera?

  Yeah.

• 26:41David McCloskey?

  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 counter-terrorism centres, right? Rather than having your own cell. So it's, it's a measure, I think, of trust in a partnership.

• 27:00Gordon Corera?

  But then it is interesting, because there's some of the cultural differences which become clear. We talked about that earlier with the, the rounders versus baseball issue. But, you know, 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, you know, a military organisation 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 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, this is not a, the way these people act, this is not normal.

• 27:44Gordon Corera?

  This is not within the military chain of command you'd have in an American, you know, organisation. So there's definitely a kind of, there's an interesting kind of culture clash.

• 27:53David McCloskey?

  Well, and I guess everybody seems exotic to everybody else, right? I mean, there's this great quote from, from Jean Howard, who was one of the women here at Bletchley, where she says, you know, "They, the Americans, were different animals. And the English they spoke had different meanings. 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.

• 28:24Gordon Corera?

  But then I do like, there's some great quotes.

• 28:27David McCloskey?

  The quotes are really good.

• 28:29Gordon Corera?

  This is from a British official during the war, which is in the authorized history of GCHQ by John Ferris. The Brit tells Deniston, the head of Bletchley, he said, "You must have noticed yourself how very many childish qualities the American male has. His taste in women, 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."

• 29:15Gordon Corera?

  I mean, that's quite a quote.

• 29:17David McCloskey?

  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 mathematicians, you wind up with a lot of former bankers who are here crunching numbers. One of the guys who came over was Art Levinson.

• 29:39Gordon Corera?

  Yeah.

• 29:39David McCloskey?

  Who has, was very fond of baseball statistics. That's something I know 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 Turing's office, it's, it's pretty dingy, it's dark, shades pulled.

• 30:00Gordon Corera?

  Yeah.

• 30:01David McCloskey?

  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 Downton Abbey style living.

• 30:12Gordon Corera?

  No, definitely not. And I think 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."

• 30:30Gordon Corera?

  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.

• 30:40David McCloskey?

  Who serves the sherry.

• 30:41Gordon Corera?

  Who serves the sherry, ends up marrying one of the Americans. She, she's one of quite a few who ends up marrying these exotic Americans with their

• 30:49David McCloskey?

  With their childish qualities.

• 30:51Gordon Corera?

  Very many childish qualities. Seems strangely attractive to some British women. I don't, don't quite understand that. But anyway, there you go. But yeah, Art Levinson is a good example of one of those code breakers who comes over and who starts seeing the value of, 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 remember why the German commander Rommel is kind of raging about why every one of his supply ships is being sunk by a British destroyer. And, and Rommel is saying, "It can't be coincidence, it's the damn machine."

• 31:36Gordon Corera?

  And Rommel has clearly worked.

• 31:37David McCloskey?

  Was that message then typed into the machine?

• 31:39Gordon Corera?

  Yeah, exactly. And they've intercepted it. And so they hold their breath because they're thinking, Rommel's maybe worked out that Enigma is vulnerable and that's why all these supply ships are being. But, 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, Rommel and some others occasionally think, maybe, maybe that's why these things are happening.

• 32:12David McCloskey?

  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, 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?

• 32:41Gordon Corera?

  Yeah.

• 32:42David McCloskey?

  Because you don't have a German Bletchley.

• 32:43Gordon Corera?

  No, I mean, they have some good individual code breakers. And actually, in North Africa, for instance, there's a very good code breaking team assigned to Rommel and to others. But, but the problem is, they never join forces. I think they have, 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, and build on them and,

• 33:25Gordon Corera?

  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.

• 33:34David McCloskey?

  And Turing was a bit skeptical of the Americans' contributions on the cryptography, wasn't he? Because, and he has this, 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."

• 33:55Gordon Corera?

  Yeah. Yeah, that's what they think.

• 33:57David McCloskey?

  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.

• 34:08Gordon Corera?

  Yeah. But, 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 Bletchley. 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'll run, they're also running bombs here at Bletchley, also a place called Iskut. And the messages are being passed back and forth over the Atlantic for the American machines to break as well.

• 34:50Gordon Corera?

  So you start to see that, as well as the individual code breakers that the Americans can send over, they are actually providing something quite important in that relationship.

• 35:00David McCloskey?

  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.

• 35:10Gordon Corera?

  Yeah.

• 35:10David McCloskey?

  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.

• 35:24Gordon Corera?

  Yeah.

• 35:25David McCloskey?

  Of the German military and navy. But there's a level above that.

• 35:30Gordon Corera?

  Yeah.

• 35:31David McCloskey?

  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 Turing's efforts.

• 35:41Gordon Corera?

  Yeah. And that more advanced code that they're using at a kind of strategic level is the one that Colossus, the world's first semi-programmable computer, which is built here at Bletchley Park, is going to be designed to crack. And it's, 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, the German high level system.

• 36:21Gordon Corera?

  And he can remember decoding a 70,000 character account by Rommel of his inspection of defences along Normandy before D-Day.

• 36:30David McCloskey?

  Imagine why that would have some value.

• 36:32Gordon Corera?

  Yeah. If you're planning to.

• 36:33David McCloskey?

  To invade.

• 36:34Gordon Corera?

  To invade, knowing where the defences are, because you've intercepted the message, mapping them out, is brilliant. And, and it's the detail, because it locates a German Panzer division just close to where the US 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.

• 37:09David McCloskey?

  I guess a lot of the claims around the impact that Bletchley has had center on, well, by how many months or years did it shorten the duration of the war? I mean, I think some of them say, well, it's 18 months, maybe two years. I mean, what, what's your sense, after looking at it, of kind of the impact on the conflict? Or is that even a useful measure?

• 37:27Gordon Corera?

  Actually, I don't think it's a useful measure. I, I think this idea, you can say, well, it would have been two years longer or 18 months longer without Bletchley. I mean, it, I don't think it kind of works like that.

• 37:36David McCloskey?

  Yeah.

• 37:37Gordon Corera?

  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. But 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.

• 37:57David McCloskey?

  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 the 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 are and you can reroute shipping lines, you know, it's, it's probably tens, if not hundreds of thousands of lives saved purely by the efforts here at Bletchley. And, I mean, who knows, counterfactuals are counterfactuals, but who knows how those really dark years of 1941 and 42 go, in terms of just being able to resupply Britain.

• 38:38Gordon Corera?

  Yeah.

• 38:38David McCloskey?

  If you don't have it.

• 38:39Gordon Corera?

  Yeah.

• 38:39David McCloskey?

  So it's, it, yeah, I agree, that the, 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.

• 38:56Gordon Corera?

  So there, I think with the war coming to an end, Bletchley's legacy isn't over. So let's take a break and look at what it means for the special relationship afterwards.

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• 41:37David McCloskey?

  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...

• 41:54Gordon Corera?

  It does.

• 41:55David McCloskey?

  It does.

• 41:55Gordon Corera?

  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 this something called the British-USA Agreement, BRUSA, which is...

• 42:13David McCloskey?

  Original. Good name.

• 42:14Gordon Corera?

  BRUSA is a good name. Made in 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, but yes, I mean, the question is, at the end of the war, what's going to happen to codebreakers and to this world? Because if you look after previous conflicts, there's this pattern where the budgets get cut, you know, the codebreakers get disbanded because it's seen as a kind of wartime necessity. And they go, everyone goes their separate ways and people go back to civilian life and to other, other normal activities.

• 42:59Gordon Corera?

  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, the thing is that both on the individual level of those integries, the people who've been integrated into Bletchley, they can see the value that it's brought. But also, at the very top level, politically, the leadership, the military leadership, the political leadership, they can see the value of, of joint codebreaking.

• 43:37David McCloskey?

  Well, it's also, I mean, frankly benefited by the fact that at that point in time, beginning of the Cold War, Britain's global role 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 governs a lot of the intelligence partnership today, is if

• 44:16David McCloskey?

  both countries bring 10 units and share, that means both countries have 20 units, right? And fundamentally, that, that math just holds up if you have a real convergence of national interest at the geopolitical level.

• 44:31Gordon Corera?

  And which you've got, because I guess it is so crucial that as soon as the war is ending, the Cold War is starting. I mean, 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, 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,

• 45:14Gordon Corera?

  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.

• 45:24David McCloskey?

  Yeah.

• 45:25Gordon Corera?

  Because the Brits were working against the Russians in the 20s and 30s and a bit in World War II, whereas the Americans had never really focused on the Russians. And so for that reason as well, the Americans are thinking, well, you know, 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.

• 45:46David McCloskey?

  Yeah. And you can even see that 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.

• 46:00Gordon Corera?

  Yeah.

• 46:00David McCloskey?

  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, you know, NASA and CIA. So the alliance, though, gets deeper in 46.

• 46:19Gordon Corera?

  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, 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 commitments that they promise each other.

• 46:59David McCloskey?

  And I mean, one of the stipulations is to promise honesty and openness with each other, which obviously we do all the time, right?

• 47:08David McCloskey?

  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, I mean, 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, is really, really important. So that's, 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.

• 47:47David McCloskey?

  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 of having this whole thing leaked in the aftermath. These agreements really sew that up so that doesn't happen.

• 48:02Gordon Corera?

  Yeah, that's right. And they, the secrecy extends to the fact that no one who knows the secrets of this joint codebreaking work could be put in any position where they could be captured or subject to interrogation. So that's actually one of the stipulations, to try and maintain that secrecy. They also agree not to spy on each other, which maybe is something we should come back to, because, you know, that's, that was the mistrust that came out in 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 worst. I mean, that's when you start to see the institutions, which are the modern institutions, forming because Bletchley is going to close down.

• 48:45Gordon Corera?

  It's going to move to the outskirts of London briefly, but then they'll move codebreaking 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...

• 49:10David McCloskey?

  That would have been a mistake.

• 49:12Gordon Corera?

  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, there's good communications lines. And then meanwhile, in the US, you're also going to get the evolution of codebreaking into more formal organizations and institutions.

• 49:32David McCloskey?

  Which I think really, the impetus of Pearl Harbor in the sense that the, 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, of the modern NSA underneath the military.

• 49:56Gordon Corera?

  Yeah. And that's still one of the differences, isn't it? Is that whereas GCHQ is a civilian, 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. There's a little bit of tension about whether, whether the Americans can talk to the Canadians direct or whether, whether they have to go through Britain and, but it, you know, eventually it's worked out that this is going to be the best way of, of organizing themselves. Still little tensions, though. It's kind of interesting. I find some of this, for instance,

• 50:37Gordon Corera?

  Britain actually offers some of its colossus, these computers, early computers, to the Americans. The Americans turn it down and the Brits realise, one of the reasons they're turning it down is because they want to build them themselves. You know, they don't want to be dependent. You know, 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 realising that there's a benefit in working together, but also not being too dependent is something which is there. But on the whole, the realisation will be two heads are better than one or five heads are better than one.

• 51:22David McCloskey?

  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 geopolitics of the Cold War happening, that doesn't happen. And then you end up with this, you know, I think of really an information system inside this Five Eyes that, in and of itself, creates the conditions for more

• 52:06David McCloskey?

  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.

• 52:20Gordon Corera?

  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 poles bringing, bringing a different way of looking at the problem of Enigma, you get the same thing, I think, with code 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, 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

• 53:02Gordon Corera?

  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's, 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 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 One, he's breaking

• 53:45Gordon Corera?

  codes on the border between India and Russia in the 1920s and the Soviet Union. And he's there in World War Two at Bletchley and then he's there in the computer age in the NSA, you know, through to, through the 70s as a Brit who suddenly seconded to the NSA. And you kind of get, that's an amazing example about how, how close those relationships are.

• 54:09David McCloskey?

  He ends up inducted into the NSA's Hall of Honour, right?

• 54:12Gordon Corera?

  Yeah.

• 54:13David McCloskey?

  I don't know how many other kind of foreign nationals are in there, but it can't be that many.

• 54:17Gordon Corera?

  No.

• 54:17David McCloskey?

  And John Tiltman's one of them. And Anne Keast 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 code breakers work side by side and that continues to this very day. And GCHQ's Cheltenham, Manchester and London hubs and NSA offices from Fort Meade to San Antonio. They still have integraries, as they're called, I mean, working together in each other's organisation. So, and you got, apparently, she must have leaked that there's an NSA hub in San Antonio, Texas, not far from where I'm from.

• 54:59Gordon Corera?

  I didn't know that. She's just declared it.

• 55:02David McCloskey?

  She's just declared it.

• 55:03Gordon Corera?

  So like a Yardley Star reveal for Anne Keast Butler. But also, it's funny, someone, I was talking to someone who used to work at GCHQ for many years and they, they just gave me a small example of how, 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, that you swipe in, pass barriers to get into the, to 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 US 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, they're built for joint working, which came out of the

• 55:48Gordon Corera?

  integration, which was here. And it, 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, was taken out by a terrorist attack or by a nuclear weapon or something like that. And the idea was that GCHQ in the UK would take over the US Signals Intelligence, you know, would become the headquarters and the base for it.

• 56:12David McCloskey?

  Which is crazy.

• 56:12Gordon Corera?

  Which is crazy when you think about it. Yeah.

• 56:14David McCloskey?

  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.

• 56:28Gordon Corera?

  Yeah.

• 56:29David McCloskey?

  And it's, it's insane.

• 56:30Gordon Corera?

  It is insane. Although I like the, the British parallel, which was that, 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, the NSA.

• 56:54David McCloskey?

  Move it to the NSA.

• 56:54Gordon Corera?

  Put it over 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, can't, can't let go of that.

• 57:04David McCloskey?

  It's our childish ways, you know?

• 57:08David McCloskey?

  I also think, I mean, the, the Signals Intelligence piece in particular, because the systems and the installations are so capital intensive, it creates a, a logic behind that integration that I don't think you see in the same way on the human intelligence side, where it's, it's still a bit more transactional.

• 57:30Gordon Corera?

  Yeah.

• 57:31David McCloskey?

  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.

• 57:49Gordon Corera?

  Yeah. You can't imagine the CIA handing over control of its operations to MI6, can you?

• 57:54David McCloskey?

  No. That's, that's a little bit harder. That's a little bit harder to imagine. And that, that human stuff still is, the signals, how 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.

• 58:19Gordon Corera?

  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 at Bletchley 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, you know, where are we now, 85 years on, is still going.

• 58:47David McCloskey?

  Still going. It's had its hiccups recently.

• 58:49Gordon Corera?

  It's had its hiccups recently, but it's still going.

• 58:52David McCloskey?

  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 really deep institutional connections at all levels, really. You know, this isn't four 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, 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

• 59:38David McCloskey?

  is really hard to unwind, even if someone wanted to purposely, it would be very hard to do that.

• 59:45Gordon Corera?

  Very hard and 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.

• 59:54David McCloskey?

  Our successors.

• 59:54Gordon Corera?

  Maybe. I'm not sure we'll be around in 85 years to find out. But that feels like a good place to, to leave the story of Bletchley Park. We hope you've enjoyed it. A big thank you to those who've joined us in person. 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 the, what goes into code breaking, the genius of it, but also the hard work and all those people who dedicated, you know, so much effort in absolute secrecy for those wartime years, which made a huge difference and laid the foundations for where we are today.

• 1:00:33David McCloskey?

  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 therestisclassified.com or 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.

• 1:00:53Gordon Corera?

  See you next time.

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