ATOMIC SPIES, PART 2: NUCLEAR FAMILIES

True Spies, Episode 161 - Atomic Spies, Part 2: Nuclear Families

NARRATOR: This is True Spies, the podcast that takes you deep inside the greatest secret missions of all time. Week by week, you’ll hear the true stories behind the operations that have shaped the world we live in. You’ll meet the people who live life undercover. What do they know? What are their skills? And what would you do in their position? I’m Sophia Di Martino, and this is True Spies from SPYSCAPE Studios.

PAUL BRODA: You could scatter these radioactive isotopes and make large areas uninhabitable. And that was the centerpiece of why he then acted on his own initiative to give information to the Soviet Union.

NARRATOR: Atomic Spies, Part 2: Nuclear Families. When we hear about some of the great spy missions, it’s sometimes easy to forget that behind each adventure is a human being who, to the people closest to them, represents much more than just an entry in an MI5 or FBI file. True Spies are more multidimensional. 

PAUL BRODA: Alan had a profound effect on me in terms of my musical interests and in many other ways in my life helping me to become a scientist, for instance. I remember particularly him taking me to a concert in the Senate House in Cambridge when I was about 15, where Myra Hess played the last three Beethoven sonatas. I will never forget that. 

NARRATOR: This is Paul Broda, a geneticist and former professor of applied molecular biology at Manchester University in the UK. His long career has taken him all over the world and, now in his 80s, he resides in Edinburgh, Scotland. One of the people who encouraged Paul in his pursuit of science was his step-father, the physicist, Alan Nunn May who just so happens to have been a convicted atomic spy. 

PAUL BRODA: Alan Nunn May became my stepfather when I was 14. My single mother was an Austrian refugee doctor in Cambridge. 

NARRATOR: When Alan died in 2003, he left two volumes of an unpublished memoir that he wrote some 50 years after his foray into espionage. Paul used extracts from this, along with letters and newly released MI5 files to write Scientist Spies: A Memoir of My Three Parents and the Atom Bomb. The other parent being his biological father, Engelbert Broda. In this episode, you’ll learn how explosive world events turned scientists into secret agents - and you’ll understand the deep crisis of conscience that these men faced as the architects of a new era in warfare. But let’s start with our protagonist, Alan Nunn May. Born in 1911, he was the youngest of four children. Unlike Klaus Fuchs, our atomic spy from the previous episode, Alan’s family was not particularly political. Nor was he an émigrée or a refugee.

PAUL BRODA: Alan was utterly English. He came from a family of brass founders in Birmingham. They had conservative values. 

NARRATOR: His eldest brother, Ted, was a decorated soldier who’d served in WWI. His other brother, Ralph, was a metallurgist by training and his sister, Mary, was a medical secretary. 

PAUL BRODA: The main activity in the family was musical - of the Gilbert and Sullivan variety - and Alan, who was quite delicate and was educated at home, first learned the piano and was the accompanist for the rehearsals and suchlike. 

NARRATOR: Alan soon moved to King Edward’s in Birmingham, one of the top schools in the country, where he excelled at math. This very British, rather quaint family life would be rocked, however, when the family business hit hard times during the Great Depression. 

PAUL BRODA: The business collapsed and there were straitened circumstances and Alan was suddenly confronted with the fact that, unless he did well, he was going to end up as an accountant. So he [took] the Cambridge scholarship exams and ended up with a scholarship at Trinity Hall, Cambridge.

NARRATOR: Interestingly, during Alan’s time, Trinity Hall wasn’t just turning out future physicists, philosophers, and politicians. 

PAUL BRODA: Trinity Hall is partly known for the fact that Donald Maclean of the Cambridge Four was also a student there. 

NARRATOR: The Cambridge Four were British members of a Soviet spy ring that penetrated the UK's intelligence community, and passed vital information to the Soviets during World War II and the early stages of the Cold War. Recruited while undergraduates at the University of Cambridge, the original members of the ring were Guy Burgess, Anthony Blunt, ’Kim' Philby, and Donald Maclean who was at Trinity with Alan. 

PAUL BRODA: But Alan asserted very strongly that he never knew Donald Maclean and his route to ending up as a spy was quite different from those people. 

NARRATOR: Alan’s distrust of the British establishment started long before he enrolled at Cambridge, while he was still at school. Alan was a diligent student, but an introvert. 

PAUL BRODA: And he did compensate by reading a lot. His father had a subscription to the Birmingham Subscription Library, which was in the middle of town, and they had open shelves and he read the material. For instance, Tom Payne, William Morris, George Bernard Shaw, and Bertrand Russell - also had access to their music collection, and he read widely on those things and also on politics, I'm sure. 

NARRATOR: It was at the Birmingham Central Library that Alan found the political fire in his belly. In his memoir, he writes:

ALAN NUNN MAY (V/O): “During my last years at school, I became more radical. I felt the generation had been conned about the purposes of the war, about the police peace settlement, about the Russian Revolution, the General Strike, and, above all, about the depression” (in which they had lost their family business). “I was still looking for a basic philosophy and foundation for the understanding of these questions, but I was sure that it must be very different from the conventional middle-class conservatism in which I had been raised." 

NARRATOR: If Alan’s politics were still being formed upon his arrival at Cambridge, they would soon be cemented. Many an evening would be spent engaging in late-night debates with other students, and classic Marxist texts were swapped and discussed among their friendship group. After all, the backdrop to all this was fairly bleak for a young communist; the left-wing Labour Party had been ousted in Britain in 1931 following the financial crash. Over in Germany, Hitler was gathering momentum and fascism was dominating Italy. For Alan and his friends, the Soviet Union seemed to offer a flicker of hope.

PAUL BRODA: As I said, he was not connected with the Cambridge Four. He had other roots to becoming a radical. And one of those was also that there were a number of left-wing scientists in Cambridge at the time, including his supervisor in physics, Patrick Blackett, who was a Nobel Prize winner later, and people like that were the circle to which Alan aspired. 

NARRATOR: However, Alan never lost sight of the main reason he was at Cambridge.

PAUL BRODA: He was very committed to his studies as a mathematician and then a physicist because he believed that his gift was for physics and that the only way he would make an impact in the world was through being a scientist.

NARRATOR: And his hard work paid off. 

PAUL BRODA: He got a First in physics in 1933 and was allowed to do a Ph.D. in the glory days of the Cavendish under Rutherford and Chadwick, who had just discovered the neutron. 

NARRATOR: The discovery of the neutron was central to the extraordinary developments in atomic physics that we’d see over the first half of the 20th century. Here at the Cavendish Laboratory at the Department of Physics in Cambridge, the esteemed duo of physicists, Lord Rutherford and James Chadwick, were making an impression on Alan. Rutherford was known for his impassioned lectures on atomic theory and radioactivity. Alan writes that among the visiting speakers was none other than Albert Einstein himself. The pre-war period was an exciting time of discovery and collaboration in the world of physics, and young Alan Nunn May was thrilled to be part of it. Meanwhile, in January 1933, a dark shadow was cast over Europe as Hitler was named Chancellor of Germany. Scientists from across Germany and Austria flocked to the UK for refuge, creating a petri dish of diverse knowledge and talent. Berti was studying chemistry in Berlin when the Nazis first caught up with him in May 1933.

PAUL BRODA: While there he was active in the German young communists. He was one of the first people to be arrested after Hitler came to power. And after two weeks in prison, witnessing other people being brutalized, he was deported because he was an Austrian. In Vienna, he resumed science and also his communist activities and ended up in Russia for most of the year 1936. 

NARRATOR: He was allowed to return to Vienna, and had begun to resume normal life. But that came to an abrupt end when, in 1938, Hitler annexed Austria. Berti became a refugee and fled to the United Kingdom

PAUL BRODA: And he was eventually joined by my mother, who had finished her medical qualification. I was born in 1939 in London.

NARRATOR: Berti went on to work at the Cavendish Laboratory in Cambridge on radioactivity and nuclear fission with Rutherford, Chadwick, and, of course, Alan Nunn May. 

PAUL BRODA: He turned out also to have been a spy. He was outed in 2009, long after his death, which was in 1983. 

NARRATOR: All of which gives the term ‘nuclear family’ a whole new meaning. Unlike Engelbert Broda however, Alan wouldn’t get away with it. His acts would spark a chain reaction that would end up derailing his career and reshaping the geopolitical landscape. Two years before Berti flees to the UK, Alan Nunn May - Paul’s future stepfather - has made his political allegiances crystal clear.

PAUL BRODA: In 1936 with his Ph.D. safe, he took a lectureship at King's College, London, joined the Communist Party, and visited the Soviet Union. 

NARRATOR: Alan spends a couple of years teaching at King's, and researching nuclear fission. 

PAUL BRODA: And with the approach of war, he, like others, was seconded to radar development projects on the Suffolk coast. 

NARRATOR: Radar could pick up incoming enemy aircraft at a range of 80 miles and played a crucial role in the Battle of Britain. Alan’s work on radar was making a direct contribution to what would later prove crucial to the Allies during the war effort. But there was a dilemma coming for communists. 

PAUL BRODA: Many of them had joined the Communist Party because it was considered the bulwark against fascism. And then in August 1939, a week before the invasion of Poland, there was the pact between the Russians and the Nazis that ended up carving up Poland. And the orders came from Moscow when the war broke out that this was a capitalist, imperialist war in which the Communists should not take any sides. Many people left the Communist Party, and Alan destroyed his party card, but he nevertheless remained a communist. 

NARRATOR: It was only in 1941, when the Soviet Union joined the Allies, that the situation reversed. 

PAUL BRODA: For people like Alan and Communist Party members in general, this was absolutely huge. There was this promise of aid and sharing information. This was an imperial imperialist capitalist war that was dead and they could get on with fighting the German fascist regime. 

NARRATOR: Alan’s radar research team was evacuated from the Suffolk coast to Bristol, in the southwest of England. It was here that Alan was invited to work with renowned British physicist, Cecil Powell on groundbreaking nuclear research.

PAUL BRODA: The relationship between Alan and Cecil was very close. In fact, when Cecil evacuated his family outside Bristol because of the bombing, Alan lived with them and so they worked together until Alan was then required to go elsewhere. 

NARRATOR: It was an idyllic time for Alan. Working with Powell, he was relatively sheltered from the war. But his world, and the world of many scientists working in Britain, would soon be shaken.

PAUL BRODA: What changed was that there was a visit from two other refugees, Frisch and Peierls, who came to visit Bristol in April 1940. 

NARRATOR: If you heard the first episode in our look at Atomic Spies, you might remember the significance of the 1940  Frisch-Peierls Memorandum. But to re-cap, together, Otto Frisch and Rudolph Peierls had created and outlined a mathematical formula.

PAUL BRODA: Which turned out to be absolutely horrifying for many people, was that only a small amount, a kilo or two of Uranium-235 would be needed for a chain reaction, which would be the basis for a nuclear explosion of this kind, which later was happened in Hiroshima. 

NARRATOR: The memorandum - marked ‘Strictly Confidential’ - was sent straight to the top of the British government and soon the British atomic research and development program - cryptically known as Tube Alloys - was born. A classified program to develop nuclear weapons. That’s when Klaus Fuchs, our spy from the previous episode, was brought in to work directly with Rudolph Peierels in Birmingham on the key process of ‘enrichment’ - that’s separating the one percent of the dangerously explosive element Uranium-235 from the 99 percent of the harmless element Uranium-238. In early 1942, Alan was required to move from Bristol to work as part of the Tube Alloys team in Cambridge. This was to oversee the work being done there by two plucky French émigrés; Hans von Halban and Lew Kowarski. In 1940, physicists Halban and Kowarski had managed to escape occupied Paris with a supply of heavy water, a gram of radium, and their research. Impressed, Prime Minister Winston Churchill invited Halban and Kowarski to continue their research at Cambridge. 

PAUL BRODA: The head of the Department for Scientific and Industrial Research wanted a reliable UK person to keep an eye on this group of aliens around Halban and Kowarski, who were in Cambridge because they didn't trust foreigners and also they didn't trust the science, really.

NARRATOR: The man responsible for hiring Alan was Professor James Chadwick. Remember Chadwick? He was the legendary professor that Alan had studied under during his Ph.D. at Cambridge’s Cavendish Laboratory. And some historians believe that Chadwick - who was well aware of Alan’s communist ties - chose him for the role for a reason. Was he himself a communist spy? Alan’s own writings suggest that no, he wasn’t.

ALAN NUNN MAY (V/O): “Chadwick's attitude may seem surprising and will scandalize authorities on Cold War security The truth is that Chadwick's attitude was at the time perfectly normal and unavoidable. This was a war against fascism in which Russia was our ally. So a history of resisting fascism and of support for Russia was no bar to recruitment, even a positive recommendation. In any case, there were precious few good scientists available, and if Chadwick had followed the criteria of the Cold Warriors, he would have been unable to find anyone for the job.”

NARRATOR: In short, they needed Alan’s expertise. This was a time for action, not prevaricating.

PAUL BRODA: No one knew how far the Germans had got, and there were even odds that they would get the bomb first. After all, they had supplies of uranium. You could mine that, and they had supplies of heavy water. So it was quite likely that they had thought of all the things that people in the West had thought of. And so, that made it extremely important to get there first. 

NARRATOR: It was also clear that 1942 had been a grim year for the Red Army. They were putting up a determined resistance at the Battle of Stalingrad, but Soviet forces suffered huge casualties. In the end, around 40,000 civilians died. 

PAUL BRODA: It was recognized that the Russians were doing all the fighting at a huge cost, And so, people really did put their prejudices to one side and really admired the Russians and the Soviet Union. And that was the high point for the Communists. I mean, a lot of people joined the Communist Party at that time. 

NARRATOR: Although he was reluctant to move from Bristol and oversee this new team as the senior ‘non-refugee’, he recognized that the work they’d be doing could be the difference between victory and defeat for the Allies. 

PAUL BRODA: After all, Alan, as a communist, had as much interest as anybody else in defeating fascism and ending the war.

 NARRATOR: Alan was immediately given a special assignment when he joined the Tube Alloys team at the Cavendish Laboratory. He was to assess a report which had come from the United States entitled ‘Radioactive Poisons’. It was a report which had left his American counterparts sick with fear. 

PAUL BRODA: This was a report which showed that the products from nuclear reactions of a sort which were technically reachable, could be used as a dirty bomb. That is to say, you could scatter these radioactive isotopes and make large areas - in kilometers of areas - uninhabitable. 

NARRATOR: Alan played out the possibilities in his head. He envisaged a situation where the Germans were facing defeat in Stalingrad and decided to use the bomb. This was his response: 

ALAN NUNN MAY (/ O): "It seemed to me that if the Germans did ever use this weapon, they would be far more likely to use it against the Russians than against the West. This was where the really critical front was. And anyhow, they regarded the Russian people as subhuman and would have very little hesitation in using such weapons against them." 

NARRATOR: Alan didn't know whether the promise that Churchill had made for the free exchange of information about the nuclear program had been honored, but he strongly suspected that that had not been the case. 

PAUL BRODA: And that was the centerpiece of why he then acted to - on his own initiative - to give information through the Russians in Britain to the Soviet Union. 

NARRATOR: Alan Nunn May has been put to work as part of the Tube Alloys nuclear research program at Cambridge. He’s discovered that fission products from a working reactor could be used as poisons. That terrifying knowledge planted the seed for Alan to pass on what information he knew to the Soviet Union. Soon Alan and the team will be required to up sticks and move to a research facility in Canada. But before he leaves, Alan seeks the advice of one of his Communist Party mentors, who arranges for him to meet with a young Russian diplomat in London. Here, in what Alan describes as a rather ‘seedy cafe’, he hands over a memo summarizing the current state of the Anglo-American atomic project as he knew it.

PAUL BRODA: And then toward the end of 1942, moves were made to send this team to Canada. 

NARRATOR: Although most of the Cavendish Tube Alloys team went to Montreal in 1942. Paul’s father Berti stayed behind. In his book, Paul writes that Berti disclosed to him some years later that the reason he didn’t go was not because he wasn’t asked, but because of Paul. He, Hilde, and Paul were not permitted to go as a family, therefore he made the decision to stay. A sliding doors moment, perhaps. In another meeting with his Communist Party contact, Alan expressed concern about continuing to pass on information from Montreal. But he was reassured that by being at the center of such a top-secret project, nobody would suspect him of such a bold move. They also told Alan to avoid all left-wing entanglements and to expect a visit from a stranger, who would open with the line “Greetings from Alex.”

PAUL BRODA: They were traveling to Canada, at least he went on a slow boat, which took six weeks at the end of 1942, beginning in 1943.

NARRATOR: To further their work, the team needed a constant supply of uranium, something that was not found naturally in the UK but could be mined in Canada. But when Alan’s team finally reached their base in Montreal, they were disappointed to find that they couldn't do very much at all. Heavy water was not available. Uranium was not available. And the Americans were not providing enough information to piece the atomic puzzle together. 

PAUL BRODA: So for probably a year they were just fiddling around waiting for something to happen. 

NARRATOR: The Tube Alloys team in Canada felt as though they were trapped in the middle of some kind of power struggle between the US and Britain. 

PAUL BRODA: There were representations at a conference in Quebec between Churchill and Roosevelt in August 1943, in which it was agreed that the Americans should be less close-mouthed and more generous about helping this team develop their work.

NARRATOR: So in 1944, Alan was invited to attend meetings in Chicago to discuss progress with the US and British team working there. One key member was Enrico Fermi who had successfully assembled the world's first artificial nuclear reactor, the ‘Chicago Pile’, in 1942. Fermi’s team’s achievement allowed the US to produce the two atomic bombs which would later be dropped on Japan. Alan was able to have a front-row seat for experiments involving the ‘atomic pile’. He suggested projects that were agreed to take place in Chicago and got involved in collaborative endeavors with Enrico Fermi and the Chicago team. 

PAUL BRODA: And it is a matter of record that when he brought this information back to Montreal, it was greatly appreciated.

NARRATOR: Armed with more information, this meant Alan and the team could now get on with some real work in Montreal. A postcard from Alan, dated September 30, 1944, reached Paul’s father Berti Broda at Cavendish Laboratory. It informed him that “collaboration with the Americans was on track”. At that time, the other center of research for the nuclear project was at Los Alamos, in the New Mexico desert, where the first atom bombs would eventually be tested. An American named General Leslie Groves was the supremo of the whole operation.

PAUL BRODA: It is also the case that he was quite chatty with people at his dinner table in Los Alamos, and it became clear that he considered that the real objective of producing nuclear weapons was not so much to end the war in Europe but that the real object of having nuclear weapons was for the long term and the post-war scenario. And this was relayed to people in Chicago And of course, Alan was extremely concerned about that, that sort of hegemony that was being proposed.

NARRATOR: At this point, Alan was disillusioned about the nuclear future. So in 1945, when he was approached once again by the Russians in Montreal, he was primed for action.

PAUL BRODA: There was a sort of way in which the Russians could get in touch with him in Montreal to use his services again. So it took them over 18 months to do that. But then suddenly the Russians popped up again in Alan's life, which had gone fairly without them until then. 

NARRATOR: With the end of the war in sight, Alan was working with his team and a number of new recruits from the UK on a project based at the Chalk River Laboratories in Ottawa. This was a big deal. The team was developing the first nuclear reactor outside of the United States. Meanwhile, events had been unfolding at the Russian Embassy in Ottawa. Military Attaché Colonel Nikolai Zabotin had activated a group of sympathizers within the staff at the Canadian National Research Council. Through these contacts, he’d gotten wind of the project at Chalk River. His director in Moscow sent a message that a certain “Dr. May” who was a Communist Party member, might be a valuable source - but should be approached with caution. Alan writes about this first meeting: 

ALAN NUNN MAY (V/O): “One evening in early 1945, it may be supposed that I was minding my own business. After a hard day's work in the laboratory, probably playing a Beethoven sonata on my piano, when the telephone rang. A man with a rather marked foreign accent made sure that I was Dr. Alan Nunn May. He said he had a message from some friends of mine and could he come and see me. Intrigued by this, I said yes and gave him two directions on how to get to me. When he turned up, he used the phrase “Greetings from Alex”. This was rather a surprise to me, but not completely unexpected.” 

NARRATOR: The mysterious foreigner was called Mr. Angelov. He went by the codename ‘Grant’, and was operating from the Russian Embassy in Ottawa - but he told Alan that he had come from New York. 

ALAN NUNN MAY (V/O): “It is difficult at this distance of 50-odd years to recall exactly what went through my mind in the few seconds before I replied. I was very much influenced by loyalty to my socialist faith, by the sense of obligation to the Russian forces, which had nearly completed the destruction of the Nazi menace, and to some extent by the fact that I had made some sort of compact, as explained earlier, which was now bearing fruit. Anyway, I replied by welcoming my visitor. I had been wondering for some time whether the British and Americans had informed the Russians about the atomic bomb project. All the signs were that they had not. My American colleagues had made it clear to me that General Groves and other leaders of the Manhattan District Project were determined to use the bomb as a means of ensuring American domination for the post-war period. It seemed to me then in the highest degree, unlikely that the Americans would voluntarily share their atomic weapon with anyone, and certainly not with the Russians. I had devoted a large part of my time to securing as much information as possible from Chicago on behalf of the British. I decided that the time had come. Now I had the opportunity to extend the same help to the Russians. Fortunately, I was well-equipped for the job. 

NARRATOR: Nothing much could be done at this first meeting. But Alan and Mr. Angelov, aka ‘Grant’, arranged subsequent meetings in which Alan was to hand over typewritten documents. These would include his own summaries of the project as well as crucial laboratory reports. As Alan explained later…

ALAN NUNN MAY (V/O): “The official reports presented some difficulties since they were not supposed to leave the laboratory, but in fact, many of the senior staff did take them home for weekend reading. The way we worked it was that I borrowed a report from the library on a Friday and gave it to Angelov that evening. He returned it on the Sunday so that I could bring it with me to the laboratory on Monday morning. I kept away from the laboratory on Saturday so that anyone asking for this report would simply be told it was out in my name and that they should ask for it on the Monday”. 

NARRATOR: According to Alan, one week he and Angelov, “worked through most of the basic material available on the chemistry and metallurgy of uranium and plutonium”. He went further, and identified certain problems; like the fact that some fission products generated during nuclear reactions, particularly Xenon-135 can poison the reactor core, temporarily disabling the reactor. As Alan put it, rather starkly, it was…

PAUL BRODA: “Everything that an aspiring nuclear designer would want to know". 

NARRATOR: Angelov was the only person who Alan dealt with directly. 

PAUL BRODA: But of course, Angelov then had to deal with this material and it was sent from the Ottawa Embassy to Moscow in encrypted form.

NARRATOR: Because Alan wasn’t actually getting any feedback from the Soviet Union on his reports, he was wary about how much was being retained by the military rather than being forwarded on to the Russian scientists. 

PAUL BRODA: He thought that a way of making sure was to send a couple of samples that he had been given in Chicago of uranium a piece, some Uranium-233 and some Uranium-235 that these would be sent to Russia and that competent scientists would realize that what was going on was an active nuclear reactor. 

NARRATOR: And that was where things then became fairly disastrous for Alan. 

PAUL BRODA: The samples were sent to Russia, presumably in a diplomatic bag. But what then happened was that apart from Alan not getting any feedback through Angelov was that Angelov basically used the standard Soviet tactic to try and entrap Alan. 

NARRATOR: At one of their meetings, Angelov handed Alan a package that included a series of banknotes and a bottle of whisky - supposedly as a thank-you gift. But Alan was not stupid. He knew that accepting any kind of remuneration for his work would compromise him. If caught, he could be charged with committing ‘treason for money’. Alan suspected the Russians were trying to transfer Alan from amateur status to being on their payroll - a prospect that filled him with dread. So he turned the offer down. This appeared to offend Angelov, who implied that Alan was “ashamed of helping the Red Army”. 

PAUL BRODA: Exactly the same thing happened to my father when he was giving information in London and the KGB files say very clearly that my father said to his Russian contact that if they ever try and do that again, he will stop collaborating with them.

NARRATOR: When persuasion failed, Angelov tried a sneakier tactic. According to Alan, a parcel of supposed reports from Angelov actually contained a bottle of Red Label Whiskey and Cdn$200 wrapped around an Ottawa newspaper. Alan knew now that he was in over his head. 

PAUL BRODA: He destroyed the banknotes and got rid of the whisky. But this was used later against him to allege that he had done what he'd done for gain rather than out of principle. 

NARRATOR: This whole saga of the so-called ‘gift’ obliterated the trust that Alan had with Angelov. He was having serious doubts about continuing to spy on behalf of the Russians at all. Alan’s career reached a climactic point on September 5, 1945, when the Chalk River nuclear reactor was the first outside of the US to ‘go critical’; a term which means a nuclear chain reaction becomes self-sustaining. It’s an important milestone in the construction and commissioning of a nuclear power plant. Alan visited Chalk River for a week or so to discuss the start-up procedure. With the war over and the reactor up and running, he believed that his work in Canada was nearly over and that he’d soon be able to return to the UK. But this accomplishment coincided with the spark of another chain reaction - one that would end Alan’s career. Last time on True Spies, we learned that a cipher clerk at the Ottawa Embassy, Igor Gouzenko had defected to the West. In doing so, he exposed a Soviet spy ring in Canada that was being run by the Soviet military attaché - a ring that included Alan Nunn May. 

PAUL BRODA: Fairly quickly it became clear that there had been a leak of information and the path led to Alan. 

NARRATOR: Initially, he was allowed to return to Britain, where he had a position as head of department at King's College London. MI5 had a reason for keeping Alan in place. It was thought that by secretly following Alan back to London, he might lead them to his accomplices. But when it became clear that this wasn’t going to happen, it all came crashing down. 

PAUL BRODA: When Alan was in London and doing his job he was then arrested and charged under the Official Secrets Act.

 NARRATOR: This was in March 1946. Alan now had to decide whether to fight the case or whether to plead guilty. 

PAUL BRODA: He had mixed feelings about it, but in the end, he decided that it was the correct thing to do, partly because he didn't want to implicate anybody else but there was this business of these uranium samples. This could be represented as theft from the Americans. And if so, then the Americans had a sort of basis for asking to put him on trial in Canada or else even worse, in America. And remember that the Americans have the death penalty.

NARRATOR: So Alan decided he would be better off among friends in Britain and pleading guilty than being extradited to America or Canada. 

PAUL BRODA: Indeed, he also, after all, was not ashamed of what he had done. And by pleading guilty, he was able to make a statement about what he had done and why he had done it, and to choose to say only what he wanted to say. 

NARRATOR: When the cipher clerk who was sending the information to Russia defected to the West, he revealed that Alan had been given the so-called ‘gifts’. But fortunately for Alan, he could not be charged with treason. That only applies when information is passed to an enemy. And the Soviets were, for the time being, Britain’s allies. Alan’s lawyer proclaimed that his activities were born from a simple desire to share scientific knowledge throughout the world. This did not lead to a more lenient sentence. In May 1946, he was sentenced to 10 years of hard labor. He served six, eventually being released from Her Majesty’s Prison Wakefield in December 1952. 

PAUL BRODA: He felt acutely the loss of his professional life because he was a very committed scientist and now he wasn't able to do that. He actually was able to keep up with physics, in theoretical physics and in prison. And then when he came out of prison, he sat at our kitchen table and relearned physics and started working productively on another area of physics, solid state physics. But he was never going to be able to achieve his full potential. 

NARRATOR: He eventually returned to Cambridge where he met and married Paul’s mother - Dr Hildegarde Broda - but was continually blacklisted for employment and kept from the work he loved. 

PAUL BRODA: It turned out that he was being blackballed for university appointments because it was believed it was wrong for students to be taught by such an ex-convict.

NARRATOR: As we heard earlier, Paul’s biological father Berti - who was also sharing atomic knowledge with the Russians, albeit from the UK - was never caught. Well, not until long after his death, anyway. Why? Pure luck. If their roles were reversed - if Berti had gone to Montreal and Alan had stayed behind, then the fates of these two men may well have been flipped. As it was, Alan’s exposure caused a huge aftershock in British-US relations. It led to the UK becoming one of the five original countries to own a nuclear weapon. Partly as a result of Alan’s espionage, the US passed [The Atomic Energy Act of 1946] the McMahon Act, which prohibited any collaboration with foreign powers on nuclear weapons development. This led the UK to embark on its own, incredibly expensive bomb-building mission. Some historians even cite the cipher clerk’s defection (and Alan’s unmasking) as the start of the Cold War. But whether or not the sharing of scientific knowledge actually led to a safer world, I’ll leave it to you to decide. The Russians tested their first atomic bomb in August 1949, three years before the UK. And who knows - maybe the work of Alan, Klaus, Berti, and others did create a ‘balance of terror’ that prevented a so-called ‘Hot War’. Everyone will have their own opinion on these complex matters but this is how Alan reflected on it, all those years later.

PAUL BRODA: I'm often asked whether I regret venturing into espionage. My answer is that I deeply regret having joined the atomic project at all as one of the 100,000, or so, more or less directly concerned with the development of the bomb, I must be responsible for about two of the 200,000 victims of the bombs dropped on Japan. This thought saved me during my imprisonment from regarding myself as some kind of martyr. The fact that my fellow mass murderers got off scot-free and indeed were honored and bemedalled is just an example of the way justice - like wealth and happiness - is very unevenly distributed. A few get too much and most too little. Nuclear power has turned out sour in a big way and our early enthusiasm now looks decidedly odd. So I bitterly regret that I did not turn down Chadwick's pressing invitation to join the project. As to informing the Russians, this seemed then - and does now - a blindingly obvious necessity. Of course, it should have been done officially, by all the implicit obligations due to an ally who had borne the brunt of the fighting. This was pointed out at the time by many. The failure to do this was an act of treachery, first against the Russians and also against the scientists who had devoted so many years to prepare a weapon under the impression that it was to be for use against the enemy, only to find out that it was for use against the ally”. 

NARRATOR: And what does Paul Broda, in a way the son of two nuclear spies, conclude? 

PAUL BRODA: There are two phrases that I would identify. One is in their situation, knowing what they knew, what would you have done? Would you have done nothing? Or would you have acted as they did? And the other phrase, which is not mine, is the condescension of posterity. It's easy in hindsight to make sweeping remarks about what's right and what's wrong. But it's very different if you were young and faced with these very major decisions, which almost none of us have to make in life. We make our personal decisions, but not ones that affect the world. 

NARRATOR: I’m Sophia Di Martino. Join us next week for the story of Israel’s top-secret mission to capture one of the Third Reich’s most deadly and pitiless figures: Adolf Eichmann.