THE world had a Cold War flashback when it emerged that 11 members of a Russian spy ring had been uncovered living in American suburbia.

The agents, most of whom were married couples with children, pleaded guilty to conspiracy to act as unregistered agents of a foreign country before they were deported from the US to Russia last month.

American prosecutors said they had been ordered by Russia’s external intelligence service to infiltrate policy-making circles and collect information.

But, until their detection, most appeared to have led middle-class, all-American lives, working, setting up home in leafy suburbs and raising their families.

The ability to blends into ones’ surroundings is vital for successful spies – and was something one of the Soviet Union’s most successful agents – Ruth Werner, aka Ursula Beurton, codename Sonya – managed for several years in Oxfordshire in the 1940s.

Born Ursula Ruth Kuczynski, in 1907, into a Polish Jewish family in Berlin, she joined the German Communist Party at 19 and in her early 20s was recruited by the GRU, the Soviet Union’s military intelligence service.

After marrying, she accompanied her architect husband Rudolf Hamburger to China in 1930, where he worked in Shanghai.

After returning to Europe, the GRU sent her to their Moscow training centre, where she was taught codes and how to build and operate radio receivers, before going on assignments in Poland and Switzerland.

After divorcing, she married Briton Leonard Beurton, who was also a Soviet agent.

In January 1941 she embarked on her most dangerous mission – travelling to Liverpool, then on to Oxford, to start a double life as a housewife and spy.

It’s not clear why she chose Oxford as a base, but historian and former Kidlington resident, Brian Sperrin, has a number of suggestions for the decision.

He said: “At the time her parents were living with friends in Oxford, because of the air raids in London. Oxfordshire was also close to her couriers and contacts in the capital.

“And it may also have been because of the closeness of nuclear research centres and the headquarters of MI5, which, because of the bombing raids in London, had moved a high proportion of its operation to Blenheim Palace.”

The spy first rented a room in Oxford, but as her two children were not allowed there, she moved them to a boarding school in Eynsham.

Next she rented a room at the vicarage in Glympton, near Woodstock, but she wasn’t reunited with her children until they moved to a bungalow in Kidlington in 1941.

Her description of it in her memoirs, Sonya’s Report, seems to point to it being one of a row in Oxford Road still standing today.

As a housewife and mother, Ruth, as she was known, was able to blend easily into the village, becoming friends with her next-door neighbour, the wife of a bricklayer.

Mr Sperrin said: “As with all the properties she lived in while in Oxfordshire, Sonya installed a radio receiver and transmitter, (which was illegal during wartime) and not long after her arrival in Kidlington, she recruited a young RAF technical officer, who supplied her with information on some of the newest developments in aeroplane research, which she passed on to Moscow.”

Another of her recruits was a man who worked at one of Oxford’s car plants, whom she trained as a wireless operator, capable of replacing her if she was unable to send messages.

But the biggest fish she netted was Klaus Fuchs, a nuclear scientist, who was working on the development of the atomic bomb.

She would meet Fuchs in Banbury or on cycle rides into the countryside, so he could pass details of nuclear research to her, speeding up the Soviet Union’s own bomb programme.

Sonya’s meetings with Fuchs began around the time she had to leave Kidlington in the autumn of 1942 to move to Summertown, in Oxford.

As Mr and Mrs Beurtons, she rented Avenue Cottage, in George Street.

In May 1945, just after the Second World War had ended in Europe, Sonya moved once more, to a house called The Firs in the village of Great Rollright, near Chipping Norton.

The family lived in the village for the rest of the decade – Sonya’s mother is buried in the village church, after she died during a visit, and her father was also buried there soon afterwards.

By this time, the Beurtons were being watched by MI5, with their post being opened.

In 1947, they were interrogated as suspicions grew about Fuchs and Sonya’s refusal to answer questions led the interrogators to suspect Soviet training and they took her silence as a tacit admission of guilt.

As the net closed on Fuchs in late 1949, Sonya and her family fled England for East Berlin. She spent the remainder of her life there, becoming a writer.

Fuchs, who was jailed in 1950 for 14 years for espionage, finally identified her as his contact in November 1950.

Mr Sperrin said: “I became interested in Sonya when I read a book by Chapman Pincher, who said that she had lived, like me, in Kidlington.

“I read her book, Sonya’s Report, and the more I read, the more remarkable I thought her story was.”

He added: “According to David Burke in his book, The Spy who came in from the Co-op, Sonya even recruited Roger Hollis (later Sir Roger Hollis and head of MI5) as a spy, though it has never been proved that he was a Russian agent.

“And so highly valued was the intelligence she obtained, during her time here, that the wartime chief of the GRU, is alleged to have said: “If we had five Sonyas in England, the war would end sooner.”

Sonya was twice awarded the Order of the Red Banner for her services to the Soviet Union.

She died in Berlin in 2000, aged of 93, but remains one of the most intriguing figures in the world of espionage.

Mr Sperrin said: “She was, in my opinion, one of the top spies ever produced by the Soviet Union and her penetration of Britain’s secrets and MI5 possibly went far deeper than was thought at the time she was operational.”

After an intelligence service deal following the collapse of the Eastern Bloc at the end of the 1980s, Sonya was allowed to return briefly to Britain in the early 1990s, when she was interviewed by former Oxford Mail journalist Don Chapman.

Recalling his interview, Mr Chapman said: “I remember meeting her and going round north Oxfordshire with her. She spoke very good English, as you’d expect from a top spy, and she was obviously a tough cookie.

“We had lunch at a pub and visited the ‘spy seat’ in the grounds of Overthorpe Hall, near Banbury. That is supposed to be where Fuchs whispered to her the secrets of the atomic bomb.

“I wanted her to show me the tree where she was supposed to have left notes for pick-up. But she couldn't remember it.

“She was a very interesting lady. I remember her telling me that she had to beat a hasty retreat, but I got the impression that it had all ceased to be important to her.”

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