Oppenheimer: How Lesmahagow produced Britain’s first atomic spy

Instead, the remarkably intelligent Scot was listening intently for secrets and snippets that he could deliver to his Soviet Union masters.

As the Second World War raged and the race began to develop the weapon of all weapons, Cairncross – from a world of hardworking coalminers, polar opposite to the snobby characters of Westminster and his alma mater, Cambridge – would share some of his homeland’s most sensitive secrets.

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This week marks 110 years since the birth of the man dubbed Britain’s first atomic spy: the secrets Cairncross passed to the Soviet Union are said to have included sensitive discussions about British scientists’ atomic programme and US counterparts involved in the Manhattan Project.

Spearheaded by nuclear physicist J. Robert Oppenheimer, the Manhattan Project led to the development of the first atomic bombs – a story set to grip cinema audiences as the film bearing the Oppenheimer’s name starring Cillian Murphy is released around the country.

Cillian Murphy as Robert Oppenheimer (Image: Universal Pictures)

While it focuses on the development of the world’s most deadly weapons and the torment that accompanied creating them, in the background was a febrile race involving warring nations for information, with Cairncross, a slightly hapless spy said to have a cantankerous personality and a sizeable chip on his shoulder, playing his part.

Years later, Cairncross would be unmasked as ‘the Fifth Man’ in the shadowy Cambridge spy ring that passed some of Britain’s most tightly guarded secrets straight into Soviet hands.

Branded traitors with lavish and sleazy tastes, its key members, Guy Burgess, Donald Maclean, Kim Philby and Anthony Blunt, became household names, synonymous with treachery and self-serving behaviour that put the nation at risk.

Unmasked and vilified, Maclean, Burgess and Philby fled to Moscow, while Blunt, with connections to the very peak of British society, was granted immunity from prosecution.

The so-called Fifth Man would only be revealed after the fall of the Soviet Empire.

It meant that Cairncross, born on 17 July, 1913 at Pine Cottage, Lesmahagow, would avoid the much of the public’s fury, and live out his life without being formally held to account for his treacherous actions.

John Cairncross (Image: Getty Images)

According to Chris Smith, author of Cairncross biography, The Last Cambridge Spy, he believed his trade in secrets was for the greater good, and that sharing even ‘ultra’ secrets from the home of codebreaking, Bletchley Park, smuggled out down the leg of his trousers, that would aid Britain’s war effort.

With a brilliant mind and flair for languages, Cairncross had worked his way through Glasgow University, the Sorbonne in Paris and to Trinity College at Cambridge.

A hotbed of radical thinking and bright young things in the 1930s, discontent over the collapse of the Labour Party vote and a rise in fascism on the Continent, saw hundreds of young, idealistic students – including Cairncross - tapped by Soviet agents.

He would be a precious resource, working for the Foreign Office and Treasury before becoming private secretary to the Chancellor of the Duchy of Lancaster, Lord Hankey – a position that gave him full access to cabinet papers.

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By September 1940, Hankey was a Minister without Portfolio sitting on various scientific committees, including the MAUD Committee established to look into the possibility of developing an atomic bomb.

Just what he passed on isn’t known, but any information from within the committee would have given the Soviet Union useful insight into Britain’s approach to the prospect of atomic weapons.

“It seems there’s a reasonable possibility that the allegation he is the first atomic spy is true,” says Smith.

“But this is not the Manhattan Project in the US. It’s still the early years of the war, things are in their infancy and there are far more important spies later, such as Klaus Fuchs.”

Fuchs, who once studied at Edinburgh University, supplied information from the Manhattan Project to the Soviet Union during and after the Second World War.

While information from the MAUD committee probably did reach Moscow via Cairncross, it was a drop in the ocean compared to thousands of documents he passed on – and more damage may well have been done while he was based at codebreakers’ headquarters, Bletchley Park

“Cairncross was working for the Foreign Office in 1936, at the outbreak of the Second World War, when he access to British foreign policy,” adds Smith. “Some of it is minor – a dispute about a rock off Gibraltar that’s not hugely interesting to the Soviet Union.

“But policy towards Nazi Germany and fascist Italy and what’s going on in the Far East, would matter.

“He moves to the Treasury and that matters as well – what are the British spending money on? From a Soviet point of view, he could supply information about how money is being spent.”

When Lord Hankey leaves the cabinet, Cairncross is moved to Bletchley Park to work as a translator and writing intelligence reports.

“He studies lots of Allied intelligence and takes documents that are going to be destroyed, puts them down his trousers and walks out,” says Smith.

“It’s incredibly risky and could be a disaster for all.”

Cairncross, however, believed that by helping the Soviet Union, would ultimately help Britain’s war effort.

And when information he supplied to the Red Army regarding German aircraft has a pivotal part in helped Russia win the Battle of Kursk, he awards himself a share of the credit.

By the 1950s and with suspicions growing around the Cambridge spy ring – and having confessed to minor spying activities - he drifts into self-imposed exile, working in Europe and America.

A more thorough picture of his involvements, however, would emerge years later, when confronted by an MI5 agent while working in America, he confessed.

But with no evidence or formal statement, Cairncross escapes punishment and is not prosecuted.

It would take until 1990 for him to be finally ‘outed’ as the Cambridge ring’s mysterious Fifth Man by Oleg Gordievsky, a KGB defector.

Smith believes Cairncross’s motivation to turn traitor lies at home, in his Lesmahagow working class background.

“He was very bright, from a lower middle-class family that is not wealthy and ends up at Trinity College which is very upper middle class.

“He finds he has the wrong accent; he’s not got the same money as other people and he feels he’s not treated with the same respect he thinks he is due.

“He joins the Foreign Office, that most exclusive and snobbiest of all Government departments where he is treated badly and gets bad reports for his work.

“He has worked all his life to get to this point and they’re not giving him the respect he’s due.

“I think this is more about ego than ideology – and he had a massive chip on his shoulder.”

The Last Cambridge Spy, by Chris Smith is published in paperback by The History Press.