Alan Nunn May, the first spy caught passing nuclear secrets, moved to newly independent Ghana in 1961, where he became a professor of physics at the University of Ghana until retiring in 1978.

Spy who caused British nuclear fears

LONDON - Stunned by the revelation that a British scientist was passing American nuclear secrets to the Soviets immediately after World War II, diplomats feared the scandal could result in Britain's exclusion from U.S. atomic weapons programs, documents released Friday revealed.

Newly declassified papers from Britain's National Archives show the upheaval behind the scenes following the exposure in 1945 of British scientist Alan Nunn May, the first spy caught passing nuclear secrets.

"He may not be the most important of the atom spies, but he was the first," said Christopher Andrew, the official historian of Britain's secret service. "It is the betrayal of the biggest secret in the entire history of espionage."

The documents offer a rare glimpse into Britain's fears of falling behind in the arms race as it sought to retain its close relationship with the newly nuclear United States.

"There's a thread running throughout that shows the British thinking if we don't sort this out, we are not going to get any secrets," said Calder Walton, a history professor at Cambridge University who is researching Britain's domestic spy service, MI5.

Nunn May was still working with the Manhattan Project — which developed the world's first atomic weapon — when a cipher clerk at the Russian Embassy in Ottawa, Igor Gouzenko, defected and named around 20 members of a Canadian-based Russian spy ring. Chief among the spies named was Nunn May, who was sent in 1943 to Canada to work on a nuclear reactor that was part of the Allied weapons project.

In one document, the unidentified director of MI5's "B" bureau — the office responsible for tackling communism — considered the impact of Nunn May's actions.

"If the Americans thought (Nunn) May was still going to be in a position to get information on atomic research, they might decide to cease collaboration with us on the whole (atomic) project," he said in the memo dated September 1945.

Such exclusion would have been particularly painful for Britain, which owed its survival during World War II in part to its close relationship with the United States — ties that still endure.

But the fear proved well founded. Congress passed the Atomic Energy Act in 1946, banning the release of nuclear technology to other countries.

"What was found out from Gouzenko, and particularly about Alan Nunn May, gave the hawks in Washington the support they needed to say that we can't even trust our closest allies with our nuclear secrets, so we have to go it alone," Walton said.

In 1952, Britain became the third country to develop nuclear weapons, after the United States in 1945 and the Soviet Union in 1949.

Among the top-secret notes are some by British agents in the United States discussing the likelihood that Nunn May, described by his code name Primrose, had stolen samples of enriched uranium during his visits to the Manhattan Project's Chicago laboratory.

"We draw your attention to this possibility since it might mean that a British scientist working in Canada had stolen and passed to U.S.S.R. atomic material belonging to U.S.A," one note said.

The documents reveal the infamous Soviet mole Kim Philby, who once led the Soviet espionage unit of Britain's counterspy agency, MI6, was kept informed of the case.

Gouzenko had revealed Nunn May's Soviet code name, "Alex," and details of a planned meeting between the scientist and his London handler outside the British Museum. Nunn May failed to show.

"No one knew why Nunn May didn't pitch up, but you can put the two together by the fact that Kim Philby was handling the case," Walton said.

In 1946, Nunn May was sentenced to 10 years in prison for violating the official secrets act.

He was released after 6 1/2 years, and the government found him work at a scientific instruments company in Cambridge. In 1961, he left for newly independent Ghana, where he became a professor of physics at the University of Accra until retiring in 1978.

He died in 2003 at age 91.