BEN MACINTYRE: The heart-stopping finale of our riveting Cold War drama 

In the final part of our spine-tingling new series by top espionage writer Ben Macintyre, we reveal how the net of the security services began to close around Soviet superspy Agent Sonya. However, thanks to the efforts of a comically inept MI5 surveillance chief, she was able to evade detention and prepared to flee back to the East . . . 

Resolute: Ursula Kuczynski — aka Agent Sonya — lived till she was 93

The picturesque hamlet of Great Rollright in the heart of the north Oxfordshire Cotswolds was remote and exceedingly quiet when Ursula Beurton moved there with her three children in 1945, just after the end of World War II.

On the edge of the village stood The Firs, a house of honey-coloured stone with four bedrooms, two sheds and an outside privy. It was without electricity, telephone and hot water, but roses grew in profusion around the door. Ursula loved it on sight. Of all the places she had lived and — in her undercover role as Agent Sonya, alias Colonel Ursula Kuczynski of the Soviet Union’s Red Army — spied in, from China to Poland to Switzerland, this house was the closest to her heart. The rent was low and a large, locked cellar ideal for storing the illegal radio equipment she needed in her double life.

Ursula began to put down roots. Though she remained a staunch Marxist atheist, the family seldom missed church, while the bell-ringers at St Andrew’s frequently came for tea to enjoy her excellent scones.

Her network of spies — now minus Klaus Fuchs, her top source, who was in the U.S. — was still supplying her with the secrets of Britain’s nuclear bomb programme, and so the transmitter was in constant use at night when the children were asleep.

Payments to her from the GRU, the Soviet military intelligence machine, were regular and sufficient. Everything was running smoothly.

And then it abruptly stopped. In the autumn of 1946, Ursula went to London for a routine rendezvous with her contact from the Soviet embassy, but he did not turn up.

There was an emergency procedure for such things. A few miles from Great Rollright was a particular row of trees, one of which had a hollow root. This was a dead-drop site where, if a meeting was missed, messages and money would be left for her. This time when she cycled there to check, it was empty, and continued to be so, leaving her low on money and worried that her spy network had been penetrated.

Her fears were unfounded. It turned out that her spymasters had got the wrong tree. And when she had failed to remove the money from the dead drop, it was Moscow that assumed it was Agent Sonya who had broken contact because the British Security Service was on to her.

Which, coincidentally, it was. The FBI in America were seeking the whereabouts of her ex-husband Rudi Hamburger, a known communist and suspected spy who had disappeared from their radar. They asked MI5 to interrogate her about him.

MI5 were somewhat nettled by the FBI’s renewed interest in Ursula. They had already told the Americans she was above suspicion, since she ‘appears to devote her time to her children and domestic affairs’.

They declined to interview her because to do so might tip off Len, her present husband — newly demobbed from the RAF and now working in a plastics factory — that MI5 was suspicious of him. Once again in this saga, the tendency to focus on the man obscured the woman, and the more important spy.

But other wheels were now turning. Alexander Foote was an Englishman who had been part of Sonya’s network of spies before she came to Britain. He had been living in the Soviet Union but managed to get away to the West, where he confessed his history as a Soviet spy, including working for Ursula in Switzerland.

He lied, telling them she had retired from the spy business long ago, severing all links with Moscow.

This, however, did not ring true to Miss Milicent Bagot of MI5, who had long been suspicious of Ursula. Once a Soviet spy, always a Soviet spy. Suddenly MI5’s hitherto tepid interest turned white hot. Letters to and from The Firs were intercepted and closely scrutinised; her bank statements were combed for evidence of suspicious money movements.

But discreet local inquiries revealed nothing out of the ordinary in her behaviour, and some in MI5 thought she couldn’t possibly have time to spy since ‘her hands are fairly full with domestic duties’.

But she was not off the hook entirely. ‘The possibility cannot be excluded that she came here with a mission,’ it was decided, and orders were given to question her, just in case.

Outfoxed and outplayed: MI5’s interrogator Jim Skardon had very little idea what he was doing

Outfoxed and outplayed: MI5’s interrogator Jim Skardon had very little idea what he was doing

The best person for the job was Miss Bagot, but instead the case was handed over to Jim Skardon, head of the surveillance squad known as the ‘Watchers’ and supposedly the country’s foremost exponent of cross-examination.

ON the afternoon of Saturday, September 13, 1947, Ursula was in her apron when she opened the door of her cottage to find a ‘Mr Saville’ and a ‘Mr Sneddon’ — in reality MI5’s Michael Serpell and Jim Skardon.

Skardon was dressed for the part of spycatcher-in-chief — a grey mackintosh and trilby, along with a thin moustache and a faintly sardonic expression. It was disguise for the fact that he had very little idea what he was doing.

Ponderous, punctilious and polite, he was startlingly unobservant and remarkably bad at his job.

His first mistake was to underestimate his quarry. ‘Mrs Beurton is a somewhat unimpressive type,’ he wrote in his report, ‘with frowsy unkempt hair, perceptibly greying, and of rather untidy appearance.’

His second error was to reveal his hand immediately. ‘You were a Russian agent for a long time,’ he declared. ‘We know that you haven’t been active in England and we haven’t come to arrest you.’

He thought he was being clever, trying to throw her off balance, but she considered his approach ‘funny and inept’ and had to stop herself from laughing. In her time, she had evaded the Chinese and Japanese secret police, the Swiss security service and the Gestapo. There was little to fear from the plodding Skardon.

He tried to get her to talk about her activities back in Switzerland and to co-operate in ‘clearing up some ambiguities’. Ursula dead-batted and, after nearly three hours of fruitless jousting, Skardon left.

In his report, he concluded that, though the Beurtons were undoubtedly communists, ‘we are reasonably satisfied that they are not at present engaged in espionage, and there is no reason to suppose that they have been for some time’.

Ursula had won the encounter, but afterwards she was rattled. Her fanatically Left-wing brother, Jurgen, had moved back to Berlin, and he now wrote urging her to come and join him in building the new communist state of East Germany.

Ursula was tempted. Though she continued to check the dead-drop site, there seemed no hope of the GRU re-establishing contact. ‘My life had run aground.’

Yet she hesitated. The children were now completely English. Daughter Nina was an ardent royalist who collect every newspaper cutting about the Royal Family and particularly admired Princess Elizabeth. Little Peter collected Dinky toys, while Michael, the eldest, had won a scholarship to read philosophy at Aberdeen University.

Could Ursula really remove her British children from the place they saw as home? How would they all adapt to life under communism?

As for herself, she liked where she was living a lot. It soothed her. ‘If I felt low, I would just wander to a favourite spot near by where I had a view across the fields and hills.’

Yet beyond Great Rollright, the world was dramatically changing, with the Soviet Union conducting its first nuclear weapons test in August 1949. Ursula felt a surge of pride. She had played a major part in making that happen.

Overnight, America’s nuclear monopoly had evaporated. Hawks in the U.S. administration had urged hitting the Soviets with atomic bombs before they built their own. Now any attack would invite an equally devastating response.

THE winter of 1949 was bitterly cold. Len was sacked from the factory. Nina’s pet mouse froze to death on the windowsill of The Firs. The water pipes burst. The GRU’s continued silence meant the Beurtons were running out of money and uncertain of the future. One morning, more out of habit than hope, Ursula cycled yet again to the dead-drop site, and this time her hand closed around a small package. With freezing fingers she tore it open: cash, and a letter granting permission for her to go to Germany to visit her brother.

After three years, Agent Sonya had come in from the cold, and things were looking good again.

And then her world crashed in around her. On February 3, 1950, she picked up the newspaper from the doorstep and felt a lurch of ‘shock and sorrow’. ‘German atomic scientist arrested’ read the front-page headline.

Klaus Fuchs had been caught — the insider who for years had supplied her with details of Britain’s top-secret atomic research to pass to Moscow before transferring to the U.S. There, as a pivotal member of the Manhattan Project, he had been helping build the atom bomb, while all the time passing the secrets of its construction to Moscow.

Unbeknown to her, Fuchs had returned to Britain four years ago and was now head of Theoretical Physics at the UK Atomic Energy Research Establishment at Harwell in Oxfordshire, where scientists were designing a nuclear reactor to produce energy. A second, secret agenda was the production of plutonium for making atomic weapons independently of the U.S.

For a time he eschewed spying, but after a year back in Britain he received instructions to meet a KGB contact in a pub. The contact, holding a red book, would bring over a beer and say: ‘Stout is not so good, I prefer lager.’ To which Fuchs would reply: ‘I think Guinness is best.’

Respectable: Major Ursula Kuczynski with children Michael, Peter and Janina in the summer of 1945

Respectable: Major Ursula Kuczynski with children Michael, Peter and Janina in the summer of 1945

From then on, they met every few months for Fuchs to hand over a fresh trove of intelligence, including key features of the new hydrogen bomb being developed in the U.S. But his past was about to catch up with Fuchs when cryptographers in America made a technical breakthrough that allowed the decoding of thousands of wartime messages sent by the KGB and GRU. Wireless traffic was uncovered which revealed that the Soviets had deployed a senior mole inside the Manhattan Project.

By July 1949, investigators had concluded that the spy in question must be Fuchs. MI5 went to work on him, but tapping his phone, intercepting his letters and surveillance produced nothing. The only way to get a conviction would be to extract a confession.

MI5 sent in Jim Skardon, who confronted Fuchs, using the same blunt approach he had attempted with Ursula. ‘I am in possession of precise information which shows you have been guilty of espionage on behalf of the Soviet Union.’

Fuchs thought for a moment and replied ambiguously: ‘I don’t think so. Perhaps you will tell me what the evidence is?’ Skardon could not. After four hours, the interrogator had got nowhere and was uncertain of Fuchs’s guilt. After a second interview, he decided he was innocent. A third was inconclusive. Skardon was maintaining his unfailing capacity to miss the spy under his very nose.

Yet Fuchs was having a change of heart. By this time he had been a spy for eight years and the strain was telling on him. He was increasingly disillusioned with the regime in the Soviet Union and had also come to admire Britain greatly, so much so that he had broken off contact with his Soviet handler.

On January 23, 1950, out of the blue, Fuchs asked Skardon to come to his home. There he confessed that he had been spying for the Soviet Union.

This breakthrough would later be cited as evidence of Skardon’s genius as an interrogator. In fact, Fuchs simply decided to tell all. Three days later, he signed a ten-page confession.

He framed his decision as a moral one. ‘I still believe in communism,’ he asserted, ‘but not as it is practised in Russia today.’ He naively believed that, having got the truth off his chest, he would be allowed to continue working at Harwell. He was shocked to be taken into custody. When she read of his arrest, Ursula felt a chill of pure fear. The newspaper reports said he had admitted passing atomic secrets to Moscow by ‘meeting a foreign woman with black hair in Banbury’. Here was a clue that would surely bring MI5 to her door. ‘I expected my arrest any day,’ she recalled.

She reasoned to herself that, though Fuchs had not betrayed her so far, he had plainly divulged some details of their meetings, and under oath in a courtroom he might reveal more. She had to act fast.

The Fuchs trial was not due to open for several weeks, so there was a window of opportunity. She prepared to defect to East Germany, all the while scanning the fields of Great Rollright for signs of MI5’s watchers.

Meanwhile, in Brixton Prison, Skardon was slowly and methodically grilling Fuchs. Shown dozens of photographs of individuals suspected of intelligence activities in the UK, Fuchs skipped over the one of Ursula.

MI5’s failure to make the obvious connection to Ursula Beurton was a counter-intelligence blunder of historic proportions. Fuchs admitted meeting a foreign, female Soviet spy in Banbury; a few months earlier, Skardon had interrogated a foreign female just ten miles away in Great Rollright who fitted her description.

And yet his latest report concluded: ‘Without further information it seems improbable that this contact will be identified.’

Ursula was making preparations for her escape, buying three air tickets to Hamburg for herself and two of the children (not Michael, the eldest, who was away at university; and not husband Len, either — he couldn’t go with her as he had broken his leg in a motorcycle accident). She packed clothes and supplies into four kitbags.

On February 18, her application to the Home Office for a permit to ‘visit friends’ in Germany was returned stamped ‘No Objection’. But she knew full well her name was on the MI5 watchlist. Sooner or later, a very loud alarm bell would sound, a notice would be sent to all airports and the door would slam shut. In the yard at The Firs, she made a bonfire of her paperwork, then wrapped the transmitter in sacking, carried it outside and buried it in the undergrowth. Today, somewhere in Great Rollright woods, lies a rusting home-made shortwave radio, a spy’s buried legacy.

Finally she climbed on her bicycle and rode towards Banbury, performing the usual counter-surveillance routine, doubling back twice to ensure she was not being followed. At the hollow tree root, she inserted a message explaining that she was quitting her post and slipping away to Berlin.

Then Agent Sonya cycled home for the last time.

A taxi took them to London Airport, Nina and Peter fizzing with excitement. In the departure lounge, the children happily played poker dice at her feet while Ursula stared rigidly at the doors, expecting the police to burst in. She resolved to say nothing if she was arrested, admit nothing.

But no one came for her. They climbed on board the plane, the air hostess more concerned with a group of inebriated Italian football fans than the innocuous woman holding tight to the hands of her two chattering children.

From her window seat, Ursula gazed out on the rain-spattered runway, where a military plane was taxiing for take-off. Instinctively, she memorised its markings. Then the door closed, the plane took off and she was gone.

The next day, after a trial lasting 90 minutes, Fuchs was found guilty of ‘communicating information to a potential enemy’ and sentenced to 14 years. Months later, Skardon visited him in prison and again showed him Ursula’s picture. ‘That’s her,’ Fuchs said, ‘that’s the woman at Banbury.’

THE Berlin that Ursula returned to was a city mutilated by war, with rubble in the streets and blackened, burned-out buildings.

She moved into a cold, one-room apartment with her children and waited for her Soviet spymasters, the GRU, to make contact.

There was little to eat and nothing to do. Yet for the first time in two decades she experienced a sensation she had never known before, and at first did not recognise — a sort of peace.

She did not feel stalked.

She had no radio transmitter to hide, no agents to contact, no need to conceal her politics.

And then she knew she had had enough of her old life. When a GRU officer finally came to see her and, with much praise for what she had achieved, invited her to resume her work, she declined. She no longer wished to be a spy.

The man from Moscow was speechless. The profession of Soviet spy is not an easy one to resign from. Anyone attempting to quit was considered a potential traitor.

But Agent Sonya was different. It was a mark of her prestige that she walked away from the spying business without recrimination, reprisal or regret.

Len joined her in East Germany, where she built a new life for herself, becoming a successful author of children’s books and living to the age of 93.

She died in 2000, outlasting, ironically, the Soviet Union and the communist cause for which she had sacrificed so much.

  • Adapted from Agent Sonya, by Ben Macintyre, published by Viking, £25. © 2020 Ben Macintyre. To order a copy for £22, go to or call 020 3308 9193. Free UK delivery. Offer valid until 12/01/2021.