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Bruno Pontecorvo

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Bruno Pontecorvo

1913 – 1993


(see long history)

The unassuming semi-detached house at 5 Letcombe Avenue was a centre of world-wide attention in October 1950. It was the home of a Harwell nuclear scientist,  Bruno Pontecorvo, and he and his family had mysteriously vanished. 

landingpage_5 Letcombe Avenue_0.jpg

Pontecorvo's house in Letcombe Avenue

M Brod, 2013

They had left for a holiday in Pontecorvo’s native Italy, and had failed to return. It was a time of hysteria over ‘atom spies’ passing details of Western nuclear weapons research to the Soviet Union. Earlier in the year, Klaus Fuchs had been unmasked as one such spy. Was Pontecorvo another?

Bruno Pontecorvo was one of the top physicists of his time. He had been working in Paris in 1940 when the Germans marched in, and escaped via Spain and Portugal to the United States. In 1943, he moved to Canada, joining an Anglo-Canadian team working on nuclear reactors. After the war, he came to England, became a British subject, and continued his research at Harwell. What he had failed to tell any of his employers was that he was a convinced Communist and therefore probably sympathetic to the Soviet Union.

In 1950 the security services realised this. He was subjected to what must have been a very painful interview, his security clearance was withdrawn, and he was found a new job teaching physics in Liverpool. It was at that point that he took his holiday. While in Italy, he was contacted by KGB agents with the news that he was being investigated by the FBI in America, and it seems to have been this that convinced him to make his move. When he finally showed up in Moscow, he claimed political persecution as the reason for his flight

His career continued successfully in the Soviet Union, where he did work of quality that could have put him in line for two separate Nobel Prizes, which eventually went to others. Whether he really had passed secrets to the Russians has long remained a matter of debate.

Frank Close

See Glossary for explanations of technical terms.

© AAAHS and contributors 2013

(see short history)

Seven miles from the Harwell and Rutherford Laboratories, a similar distance from Oxford University, and a mere stone’s throw from Culham, Abingdon has been a natural home for scientists for over half a century. This was especially so just after the Second World War, when the new secret government nuclear research laboratory at Harwell opened, and Abingdon School became a choice for the sons of the scientists.  

Klaus Fuchs, who passed secrets of the atomic bomb to the USSR during WWII, continued doing so during his time at Harwell, until his arrest and conviction in 1950. 

Another scientist living in Abingdon hit the headlines in 1950: Bruno Pontecorvo, who disappeared with his family from their home at 5 Letcombe Avenue in September, not to re-surface until five years later – in Moscow. Pontecorvo was a brilliant nuclear physicist. He had been born in Pisa in 1913, and studied under the great Enrico Fermi in Rome, where they made fundamental discoveries about the atomic nucleus. Working in Paris in 1940, Pontecorvo, who was half-Jewish, fled to the USA following the Nazi invasion. There he worked in Oklahoma for an oil exploration firm, where he developed novel ways of using nuclear physics to find the minerals that are indicative of oil deposits. His use of radioactive materials in this process attracted attention, and in 1943 he joined the Anglo-Canadian team developing a nuclear reactor as part of the Manhattan Project. His techniques were used to find uranium, which is a major ingredient of nuclear reactors and was used in the first atomic bombs. Pontecorvo himself did not work on the bomb, but he became one of the leading experts on nuclear reactors. After the war he remained in Canada for three years, until the Canadian reactor was completed, and then, at the start of 1949, joined the UK’s team at Harwell, designing the first nuclear reactor in Western Europe. 

In addition to being a great scientist, Bruno Pontecorvo was a great showman – he delighted in demonstrating his skill at riding a bicycle backwards, sitting on the handlebars – and an all-round sportsman. He played tennis at a high level, and, as a teenager, had hopes of making the Italian national team. Bruno Pontecorvo bore some similarity to Ramon Novarro, a matinee idol of the 1940s, and became famous for his elegance on court at the tennis club in Albert Park, where he was renowned for his pristine white kit and long white trousers.  

His wife Marianne was Swedish. They had three sons, the eldest, Gil, was a student at Abingdon School during 1949 and the first half of 1950. The two younger boys were named Antonio and Tito. 

Pontecorvo himself was a communist, although he had kept this secret during his time in North America and Harwell. He was also a colleague of Klaus Fuchs, and although it is established that he never had any clandestine association with that established atom spy, there has always been speculation as to whether Pontecorvo himself passed on secrets at some stage, either when in Canada or at Harwell.  

Following the arrest of Fuchs in February 1950 several spies were arrested in the USA and anti-communist hysteria grew there under the influence of Senator Joe McCarthy. During the spring of 1950, Pontecorvo was interviewed by the Harwell security officer on behalf of MI5. No definite proof of espionage was found, but it became clear that Pontecorvo, although he denied being a party member himself, had relatives who were communists. The authorities were worried, and arranged for him to leave Harwell at the end of 1950 to take up a position at Liverpool University, where security issues would not be a concern. 

However, this never happened; Pontecorvo disappeared.  

On July 25 1950 the Pontecorvo family left Letcombe Avenue to take a vacation in Italy. Pontecorvo had accumulated leave he could use and they were not due to return until 4 September. However, Pontecorvo did not return to work and Harwell became concerned, the security services were alerted, and by October it was apparent that Pontecorvo had fled through the Iron Curtain. Speculation began about what information he might have taken with him. The story hit the headlines around the world at the end of October 1950, claiming that Pontecorvo was a spy who had ’skipped just as the security services were about to arrest him’. No evidence to back this up was produced at the time, but recent research has uncovered the full story. 

Pontecorvo always claimed that he had fled because of political persecution, and cited McCarthyism which he said was threatening to spill over into the United Kingdom. There is however little or no evidence that this was so, and any ‘persecution’ may have been the trauma resulting from interrogation by the security authorities, followed by his effective dismissal from Harwell. It is now known that, shortly before Pontecorvo disappeared, Kim Philby, a senior official in British Intelligence who was a long-term Soviet agent, discovered that he was being investigated by the FBI.  By the time this information reached Moscow, Pontecorvo was already on vacation in Italy. He was contacted by KGB agents in the final week of August and took the decision to move to the Soviet Union. He was provided with airline tickets and, with his family, flew from Rome to Helsinki, where they arrived on 1 September. From there, two cars took them to the USSR.

In his subsequent life in the USSR his fortunes were mixed. On the plus side he was elected a member of the Soviet Academy of Science, and won the Stalin Prize, both of which carried significant privileges. However, not least due to his being in the USSR, he failed to get full credit for some major innovations in science. He certainly missed winning a share of two Nobel Prizes. One was for an idea about the enigmatic particles called neutrinos. He was unable to pursue this in the USSR, and the Soviet authorities prevented him leaving the country to do the experiment at CERN in Geneva. Three Americans independently had the same idea and completed the experiments in the USA, subsequently winning the Nobel Prize. Pontecorvo’s second chance was his role in predicting that neutrinos might be detected emanating from the sun. This discovery won the Nobel Prize for the American Ray Davis in 2002; unfortunately Pontecorvo had died in 1993, and the prize is not awarded posthumously.

Frank Close

This article is based on the author’s “Half-Life: The Divided Life of Bruno Pontecorvo, Physicist or Spy” (OneWorld UK;  Basic Books USA; 2015)

See Glossary for explanations of technical terms.

© AAAHS and contributors 2013


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