The spy who started the Cold War

The KGB archives are now sealed, but for a brief window in the mid-1990s a KGB officer named Alexander Vassiliev gained access to the files and began transcribing their contents. Vassiliev’s notebooks form the basis of a new book, published in the US this month, revealing Broda’s pivotal role in Soviet atomic espionage.

MI5 has also recently declassified its files on Broda, allowing the story of the spy who got away to be told for the first time. Engelbert (also known as Berti, or Bertie) was 28 when he arrived in Britain in 1938. The son of an Austrian aristocrat, he was handsome, highly intelligent and an ardent communist. As a student in Berlin and national leader of the German communist students, Broda had been imprisoned twice by the Nazis. Broda told the immigration authorities that he was a science student keen to attend a lecture at the University of Bristol. In truth, he was fleeing Nazi persecution and may already have made contact with the Soviet intelligence service. His wife Hildegarde soon followed.

The Security Service (MI5) began to take an interest in the young Austrian from the moment he set foot in this country. Indeed, his MI5 file contains a clipping from The Times of 1931, describing the murder of a communist spy in Vienna: in the dead man’s flat, Austrian police found a cache of incriminating espionage documents; young Broda was identified as the courier.

In London, Broda swiftly made contact with other left-wing Austrian refugees and within months Special Branch was reporting that Broda was “the leader of the Austrian Communist Party” in this country. A fellow member of the group was Edith Tudor Hart, an attractive Austrian-born communist who had married an Englishman, adopted British citizenship and settled in London. Tudor Hart was a radical photographer, who saw her work as a tool for propagating communist revolution. Several of her photographs are in the National Gallery.

She was also a KGB courier and agent (codenamed, not too subtly, “Edith”), with links to Soviet intelligence dating back to 1926. Tudor Hart had already recommended the recruitment of Kim Philby and his Austrian first wife Litzi to the KGB, and she now paved the way for the recruitment of Broda. Tudor Hart and Broda soon became lovers.

MI5 opened Broda’s mail, tapped his telephone and monitored his movements, but could find no evidence that he was anything other than a staunch communist and an accomplished scientist. In 1939, he was briefly interned and his flat searched, but without the discovery of any incriminating evidence. In 1941, Broda was offered a job at the Cavendish Laboratory in Cambridge, working on atomic reactors and controlled chain reactions with Hans Halban, a French refugee physicist at the cutting edge of nuclear research. Halban had fled the Nazis in 1940 and arrived in Britain carrying a suitcase containing most of France’s supply of “heavy water” used in nuclear reactors.

The Security Service objected to the appointment, noting that Broda represented a serious espionage risk. The spycatchers were overruled by the Government’s Department of Scientific and Industrial Research, which insisted Broda was too good a scientist to waste. “The exigencies of this department do override objections of security grounds,” the head of the department declared, but added complacently that “Mr Broda would not be employed on the more secret part” of the laboratory’s work.

It was a critical error: Broda was soon at the heart of the project, privy not only to Britain’s nuclear secrets but also those of the Manhattan Project, the US scientific programme to develop the first atomic bomb. Less than a year after starting work, Broda sent his first package of information, via Tudor Hart, to the KGB.

The KGB’s espionage campaign to steal the Allies’ nuclear bomb plans was codenamed “Enormous”. Broda was given the cover name “Eric”. In December 1942, the KGB station in London reported delightedly to Moscow that “ ‘Eric’ — who, since January 1942 has been Halban’s assistant in special division (devoted to Enormous) of the central laboratory on explosives in Cambridge — is completely informed about all the workings on Enormous both in England and in the US because he has access to American material on Enormous that the English had received as part of an information exchange.”

Broda was not the only Soviet spy in Britain passing nuclear secrets to the KGB. Another was John Cairncross (codenamed “Liszt”), the Cambridge-educated mole within MI6 recruited by Anthony Blunt and Guy Burgess. A third was Melita Norwood (alias “Tina”) who was unmasked in 1999. Yet another was the British physicist Allan Nunn May, who was convicted of spying for Moscow in 1946 and sentenced to ten years in prison.

The KGB was making simultaneous inroads in the US, but initially Moscow’s best intelligence came from its spies in Britain. “Soviet sources in England were the first to provide Moscow with atomic intelligence,” wrote Pavel Fitin, Moscow’s head of Foreign Intelligence (1939 to 1946), in a memo quoted in Spies by Harvey Klehr, John Earl Haynes and Alexander Vassiliev. “The material included valuable and top-secret documents [that] served as a starting point for laying down the groundwork and organising work on the problem of atomic energy in our country.”

Delighted that Broda had volunteered the first batch of information, and impressed that he seemed to require no payment, Moscow asked Tudor Hart to arrange a meeting between this willing new recruit and the KGB contact in London, codenamed “Glan” (his real identity is still unknown). Initially unwilling, Broda finally agreed to meet the KGB contact face to face, having been reassured that this comrade was not “English”. British communists, Broda said dismissively, are “generally very indiscreet”.

After meeting “Glan” for an hour and a half, Broda agreed to pass on everything and anything he could discover about the atomic bomb project, including all the “bulletins from the Americans”.

‘Eric’ reports that in their field of work, the Americans were significantly ahead,” noted “Glan”. “During the conversation, nothing was called by its proper name, but ‘Eric’ knows who it is he agreed to work for.” When “Glan” offered to pay Broda for information, he took offence. His motives, he said, were ideological, not mercenary. “Eric is completely selfless in his work with us,” said “Glan”.

What Broda did not know was that MI5, increasingly suspicious of him, had managed to recruit its own spy within the Austrian communist circle. The identity of this informant, codenamed “Kaspar”, has never been revealed, but he was a close confidant of Tudor Hart and Broda.

In December 1943, “Kaspar” reported to MI5: “Although I have no definite proof, I have always suspected Broda of being engaged in industrial espionage. In view of the intimate relations existing between Edith Tudor Hart and Broda, it must be assumed that she is well informed of her lover’s activities.” Perhaps aware of MI5’s increasing interest, Broda took elaborate precautions to avoid detection when meeting his KGB control. ‘Eric’ was supposed to mark a page of a phone book inside a designated phone booth. After entering this phone booth at a fixed time and finding the mark he had made, we would go out to meet him at the appointed place and time,” the KGB noted. He may also have passed information to the KGB through his dentist, a Russian named Schkolnikoff.

Broda’s information included the blueprint for one of the American Manhattan Project’s early nuclear reactors. The package, crowed the KGB, contains “all the necessary information to build a plant and [it] is exceptionally valuable”. When a colleague at the Cambridge laboratory went to Canada, Broda was left with “his personal key to the library containing reports on Enormous”. The KGB made a copy. Moscow now had the key to Britain’s atomic safe.

By late 1943, Broda was working on the “Tube Alloys” project, the code name for the British nuclear weapon research into the use of plutonium, whose very existence was the most closely guarded secret. He was now not simply one agent among many, but Moscow’s most important atomic spy: in August, the KGB described “Eric” as “at pres., the main source of information on work being done on E. [Enormous] both in England and in the USA”.

The MI5 files reveal the frustration of Britain’s counter-espionage officials as they struggled to snare him. It was noted that Broda had been in contact with Litzi Philby, the communist first wife of the British mole who had yet to be exposed, and met regularly with Alan Nunn May, who had joined the Cavendish Laboratories in 1942. As MI5 closed in, tensions between Tudor Hart and Broda appeared to be rising. Agent “Kaspar” overheard a row between them, with Tudor Hart accusing her fellow spy of “being too careless . . . when a man is involved in such business as he is, he ought to be careful and not endanger his friends”. With typical insouciance, Broda replied: “All our people are all right. Don’t get alarmed, don’t write and don’t phone.”

Broda never realised that “Kaspar” was betraying him to MI5, but he must have known he was in serious danger of discovery after Nunn May was arrested in the spring of 1946, and then confessed to espionage. Yet he maintained a cool front: “Broda did not appear to have expressed any view on Nunn May’s arrest beyond surprise that he should appear in court on such a charge.”

The US authorities, realising that the British nuclear programme had been compromised, began to restrict the sharing of nuclear secrets with the UK. The US would later discover how thoroughly its own nuclear programme had been penetrated by the KGB.

But Broda was by now planning his escape and in 1947 he applied for permission to leave the country, supposedly for a brief holiday. There was fresh debate within the security service about whether to allow him to go, but without firm evidence of espionage, there was little choice.

By 1948, Broda was back in Austria and firmly ensconced as a lecturer at the University of Vienna, where he would remain for the rest of his life.

As the years passed, evidence of KGB penetration of the Allied nuclear programme mounted, and within MI5 the suspicion that Broda had spied for the Soviet Union hardened to near certainty. That belief was bolstered when Broda’s former wife Hildegarde married Nunn May just a few months after he emerged from prison in 1952. The two men shared a taste in wives. What else had they shared? “We feel sure that Broda was engaged in espionage during the war, although we have no proof of it,” MI5 admitted. “Broda might well have been the person who recruited Nunn May for the Russian Intelligence Service.”

Broda’s son, Paul, remained with his mother in Britain and went on to become Professor of Applied Molecular Biology at the University of Manchester. Paul, who is writing a book about his father and stepfather, declined to comment for this article.

By 1955, the CIA had marked Broda down as “a key man in the transmission of secret atomic data from the US, Canada and Great Britain to the Soviets”. The same year, through foreign sources, MI5 learnt that Broda had “organised an information network with tentacles in every department of the chemistry institute”. Perhaps this information was shared with the German intelligence service, but if so, there is no evidence of it in the MI5 files. In 1956, MI5 issued a circular ordering that “a special watch should be put on Broda if and when he came to this country”.

Britain’s counter-espionage bosses strongly suspected that an important spy has slipped through their fingers, but only with the revelations in Vassiliev’s KGB notebooks has it become clear just how important Broda was to the fledgeling Soviet nuclear programme.

There is continuing debate over the extent to which the KGB’s spies on both sides of the Atlantic helped to speed up the Soviet atomic bomb project. Yet the reports from Fitin, Moscow’s head of foreign espionage, are unequivocal: intelligence from Broda and others laid the groundwork for Soviet nuclear scientists, paving the way for the nuclear confrontation of the Cold War.

Over time, as the Cold War divulged its secrets, Britain’s atomic spies were uncovered. Allan Nunn May emerged from jail and was blacklisted by British universities until his death in 2003. John Cairncross was unmasked as a Soviet spy in 1990 by the KGB defector Oleg Gordievsky. Melita Norwood was exposed by the defector, Vasili Mitrokhin. But Broda was never caught and took his secret to the grave. From 1955 and until 1980, he was Professor of Physical Chemistry at the University of Vienna, and a leading figures in the Pugwash movement, an international alliance of scientists concerned about the misuse of science. The movement originated in the Russell-Einstein Manifesto of 1955, which called on scientists to find ways to avert the threat to civilisation from nuclear weapons.

Broda died in 1983, at the age of 73. He is buried in a Vienna cemetery in a “grave of honour”, a tribute to one of Austria’s most distinguished scientists. Alongside that epitaph might stand another: “Eric”, the spy who got away.

Read The Times’ report of the communist student’s murder in the Archive.