He was regarded as one of Britain’s top physicists and by colleagues as a man
of unimpeachable integrity, yet he betrayed the biggest secret in the
history of espionage: passing details of the atomic bomb to the Soviet Union.
Several times after his conviction and six years’ penal servitude, Alan Nunn
May would try to explain why he came to be passing state secrets to Soviet
spies on street corners, but even on his deathbed he would not disclose who
had recruited him to serve the Russians.
For all the silence of the lonely, retiring intellectual, it now appears that
the British Security Services found out. Files released today to the
National Archives show how MI5 arrived at a startling conclusion: that after
his release from jail he married the ex-wife of the man who had recruited
him, and so remained for ever wedded to the secret.
Dr Nunn May had been working in Cambridge on what was cryptically called the
“Tube Alloys Project”, a nuclear research project that was moved to Canada
in 1943 to allow closer cooperation with the Americans. It was only in 1945
that he came to the attention of British counter-intelligence, via the
defection of a cipher clerk who walked out of the Soviet Embassy in Ottawa,
his shirt stuffed with secret documents, exposing an extensive spy ring.
A report filed with MI5 in September 1945 stated the findings: that Nunn May
“has supplied Colonel Zabotin” — of the Soviet Embassy — “with useful and
valuable information about atomic research and has further provided Zabotin
with two samples of uranium 235 and 233, which are alleged already to have
been flown to Moscow”.
Nunn May, whom the British codenamed “Primrose”, was to return to London to
meet a Soviet agent outside the British Museum on October 7. He would be
carrying a copy of The Times.
“If this contact is made,” the report continued, “it would afford an
opportunity to uncover a network of Soviet espionage which may prove at
least as extensive as that already uncovered in Canada.”
At 6.15am on September 17, an MI5 man was waiting at Prestwick airport to
watch Nunn May arrive, dressed in a grey striped suit, brown shoes,
“coloured socks” and a blue trilby. “Age 34 years but looks about 40,” the
agent reported. “Rather stern looking and wears horn-rimmed glasses with
gold sidepieces.”
Nunn May was followed to London and observed visiting a bank, meeting a man
for tea and installing himself at his new lecture post at King’s College,
but soon afterwards, “owing to his apparent uneasiness”, the watchers
withdrew, anxious not to give the game away. “We ought to be able to get
into touch with some reliable person at King’s College who would in effect
keep May under cursory observation,” a senior agent suggested. In the
meantime they tapped his phone and intercepted his mail.
The game had been given away, however; most likely by Harold “Kim” Philby, the
notorious double-agent at the heart of Britain’s Secret Intelligence
Service. Communications on the subject of Primrose frequently bear a note at
the base: “Copy handed to Philby SIS”.
Nunn May did not show outside the British Museum on October 7, nor on
subsequent days with 7 in the date, though MI5 was still watching months
afterwards. There was not enough evidence to convict him. Senior figures
considered attempting a deception — perhaps an agent posing as a Russian
contact? They discounted the idea, but they needed some sort of
corroboration.
When Nunn May was arrested in 1946, he admitted that he had passed secrets to
the Russians, to ensure that the Americans did not have a monopoly in atomic
weaponry. It was enough to earn him a ten-year sentence, but still the
security services did not know who had recruited him, nor who had tipped him
off that he was being watched.
Answers suggested themselves only after some brilliant interview work by one
of the service’s top interrogators.
The files report a failed attempt to interview Nunn May in prison in November
1946 — there is even a letter from Philby, cynically commiserating with his
colleagues. Then in 1949 an agent named William Skardon offered to try
again. Skardon reported: “The only real information I could obtain was that
his recruitment . . . took place literally a few hours before he left
England for Canada and that the individual for whom I might be looking in
this connection was well out of my reach.”
Then, soon after Nunn May’s release in September 1952, another piece of the
jigsaw puzzle appeared to slot into place.
MI5 had been monitoring the scientist as he settled back in Cambridge but were
taken entirely by surprise when, within a year, he married. Nunn May’s
wedding to Hildegarde Broda, an agent wrote a week later, “draws attention
to a connection which may have significance for us. You may have views to
express on the possibility that the Brodas played a part in involving him in
espionage.”
Broda was “a Communist sympathiser”, her exhusband Englebert was thought to be
one, too, and one who was “involved in espionage”. He was also a physicist
who had been “employed on the Tube Alloys Project during the war”. He had
worked with Nunn May in 1942. It would take a physicist to spot a physicist
who could provide information of value. He had also contacted Nunn May in
October 1945; he might even have warned the atomic spy that he was being
watched.
By 1949, when Skardon interviewed Nunn May, Englebert Broda had divorced and
moved to Austria. Checks were carried out on all those at the surprise
wedding, and some who were not, but by then, as Nunn May told Skardon, the
prize that might have unlocked the Soviet espionage ring was out of reach.
Life and times of a Soviet agent
Alan Nunn May (1911-2003), above, was the son of a brass founder He graduated
with a first in physics from Trinity Hall, Cambridge. The Russians gave him
the codename Alec Jailed for activities “prejudicial to the safety and
interest of the State” in 1946. The governor of Wakefield prison wrote: “His
attitude is a combination of ‘holier than thou’ combined with some
intellectual snobbishness” He married Hildegarde Broda, above, in 1953. In
1961 he took up a post at the University of Ghana. The family returned to
Cambridge in 1978
Source: National Archives; Times database
