Alan Nunn May

Britain's first convicted atom spy

Alan Nunn May, physicist: born Birmingham 2 May 1911; married 1953 Hilde Broda (one son, one stepson); died Cambridge 12 January 2003.

Alan Nunn May holds an important place in Cold War history as the first person convicted for supplying atomic-bomb secrets to the Soviet Union. He was jailed in 1946 and served seven years, but only on his death a half-century later has he given any substantive account of his espionage activity, in the form of a statement dictated in his final days.

A gifted nuclear physicist at King's College London in 1939, Nunn May was a natural recruit for secret wartime research, first working on radar, then on early studies for the atomic bomb, and ultimately on nuclear reactors in Canada, on the fringe of the Manhattan Project. He used this position to supply reports on nuclear progress to Soviet intelligence and to pass on stolen samples of processed uranium, but was caught when a Soviet cipher clerk defected in Canada and revealed his role.

Coming just months after the end of the Second World War, the case caused enormous shock and had profound political repercussions. Not only was it the first public proof that the Soviet Union had spied on its wartime allies and penetrated the security screen around nuclear weapons development, but it also helped ensure the end of transatlantic co- operation on nuclear matters. The results of that were Windscale, Aldermaston and the British-made bomb.

Though Nunn May pleaded guilty at his trial, he refused to identify associates or give details of his spying. He insisted in a brief confession: "The whole affair was extremely painful to me and I only embarked on it because I felt this was a contribution I could make to the safety of mankind."

This silence he maintained for the rest of his life – until now, with the release by his family of a text dictated to a step-granddaughter, Alice Evelegh, three weeks before his death. Entitled "This is a Disclosure of How I Became a Russian Spy", it appears to resolve many of the mysteries of the case while making clear that he went to his grave believing his actions justified.

Although it was known that he was left-wing and pro-Soviet before the war, Nunn May confirms for the first time in this document that he was a Communist Party member. He revealed that his first act of espionage took place in Britain after he had read a secret American report warning (incorrectly as it happened) that Nazi Germany might have the ability to explode a "dirty bomb" – one that would spread radioactive poison over a large area.

"It seemed to me that the possible danger to the Russians from the effects of the dirty bomb was even greater than the possible danger to the West," Nunn May states. "So, I took the measure of contacting the Russian Secret Service."

The effect was to establish him as an "asset" in the eyes of Soviet intelligence and, when he was sent to Canada in 1943, they instructed him to set up a radio communications station for them there. Nunn May says he thought this dangerous and, with the Soviet Union by then gaining the upper hand in its struggle with Germany, he "did not see the point" and did nothing. The war was in its final year when a Soviet agent approached him again in Montreal and asked for information on the atomic bomb. "It seemed to me that they ought to be informed," he states, "so I provided all the information I could."

Much of this phase of the story became public in 1946. Not only did he report on the reactor work in Canada, but he informed about visits he made to a Manhattan Project laboratory in Chicago which conducted advanced studies on potential fissile material for the weapons and he handed over tiny samples of two materials, U-235 and U-233.

The "disclosure" adds the following, which Western intelligence must have suspected in 1946 but which was never openly stated:

Because I had access to the entire library of research documents on nuclear power (a great deal of which was provided by the USA), I was able to borrow these documents from the library and hand them over to the agent who would take them to Ottawa, photocopy them, transmit them to Russia and then return them to me.

These activities continued even after Hiroshima.

Although identified as a spy at the end of 1945 Nunn May was not immediately arrested; MI5 allowed him to return to London in the hope that he would contact and expose other agents. He never did, and his new account confirms long-held suspicions that he was tipped off, although he does not say by whom. He was finally arrested on 4 March 1946.

How important was he, as a spy? Even today scholars struggle to establish the contributions made to the Soviet atomic project by the various "atom spies", but it is clear that Nunn May was not in the front rank alongside Klaus Fuchs and the American Ted Hall (whose role only became public in the 1990s), both of whom worked at the heart of the Manhattan Project. None the less, as a specialist scientist who was very well informed, and as a thorough and industrious spy, he has a secure place in the second rank.

His motivation will always be the subject of debate. In the new document he says he first passed on information as a matter of conscience. But later the Russians put him under pressure, perhaps to the point of blackmail. His reluctance was short-lived, and he would eventually throw himself into spying with gusto, stopping only when he was warned that the game was up.

Much was made at his trial of a gift of $200 from his Soviet contact, but even then the sum was hardly enough to provide a motive, and it now appears he was tricked into accepting it and burned the money afterwards.

Nothing in his family background gave a hint of his future notoriety. The youngest child of a middle-class Birmingham family, he won scholarships first to King Edward's School in that city and then to Trinity Hall, Cambridge. Graduating with a First in Physics in 1933, he studied for three years at the Cavendish Laboratory, where his supervisor was Jane Chadwick and he came in contact with many of the other legendary figures in Ernest Rutherford's team.

It appears to have been Cambridge that taught him left-wing ideas. Among the physicists who influenced him was Patrick Blackett, who was an ardent admirer of all things Soviet and he is also said to have befriended Donald Maclean and Guy Burgess. Nunn May did not become a "mole", however, and made no secret of his leanings, visiting the Soviet Union, becoming active in the left-wing Association of Scientific Workers and contributing to pro-Soviet papers.

On his release from prison he spent some difficult years in Cambridge working for a scientific instruments firm before taking up a post at the University of Accra in the newly independent Ghana in 1961. He became Professor of Physics and he remained in Accra until his retirement in 1978, when he returned to Cambridge.

In 1953 he had married Hilde Broda, an Austrian doctor then practising in Cambridge, who accompanied him to Accra where she continued her medical career. The family describes them as a close couple and his retirement as a very happy one.

Brian Cathcart