Unraveling a Soviet spy ring in Britain

Jürgen Kuczynski and Ruth Werner make the TV spy drama The Americans look understated


Some radio documentaries take longer than others to make. When people ask how long I’ve been beavering on my one, I say around 30 years. It springs from a fascination with a suburban spy ring active in Britain during the Stalin era that I starting tracing back in the 1980s in East Germany via the Kuczynski family.


Back then, Jürgen Kuczynski called himself a “dissident who toed the party line” and was a leading figure in Communist intellectual life in the old East – albeit a loyal party member. As a much younger man in wartime Britain, he had also been a vital link in a chain of spies, thinkers and fellow travellers, who we now know formed one of the most significant Soviet spy networks of the early Cold War. It was targeted on Britain’s emerging nuclear bomb programme and based in what was then one of London’s most fashion- able buildings in leafy Hampstead – the modernist Lawn Roads Flats.

Kuczynski and his wife set up home here, as wartime émigrés in what would become an unofficial hub of intelligence trading. As well as working on his 40-volume history of the working classes in Germany, flying through exams on economics and statistics and collecting intelligence on schisms in the Labour Party, he introduced his sister Ruth to the émigré physicist Klaus Fuchs, who was working on the joint British-American bomb project. Fuchs agreed to betray nuclear bomb secrets to Moscow as the Second World War tipped into the Cold War – and Ruth, whose code name was Sonya, was his controller.

She was “Ruth Werner” in East Berlin when I met her and had had at least four assumed names in her lifetime, all of which unlock different chapters in a tale that makes the TV spy drama The Americans look understated.

Starting out in Manchuria as a Soviet spy, she was an exceptionally adept encrypter and able to use Morse code faster than any other agent on Soviet military intelligence’s books. “The friends”, as she referred to her Moscow handlers, then decided that she should move to London, and an arranged marriage to Len Beurton, a British national (and fellow spy), which made it easier for her to get British citizenship. From 1943, she lived under the cover of a rural Oxfordshire housewife and mother, transmitting nuclear secrets to Moscow from an adapted washing line in her garden in the village of Great Rollright – near the Atomic Energy Research Establishment in Harwell.

Sonya described to me walks down country lanes with the shy scientist Fuchs – they would affect to be young lovers – while he handed over the atomic formulae.

MI5 had got nowhere in its attempts to interview her about “subversive” connections. Forty years later, I discovered what they were up against. Too pressing an interrogation would make her clam up: “You’re smearing honey in my mouth,” she once complained, when she suspected flattery was being applied to winkle out detail. I had to work my way back into the family’s affections by bringing Len a copy of the Wisden Cricketers’ Almanac – the one thing he craved from an England he had last seen during the war.

I still didn’t know the half of the story. The leak of the Soviet Mitrokhin Archive in 1999 confirmed the existence of Melita Norwood, the longest-serving British spy for Moscow, famously dubbed “The spy who came in from the Co-op” when she was exposed by the The Times. Sonya had also been her handler in the late 1940s – and before she died, she sent Norwood a copy of her autobiography with the valedictory message: “Sonya salutes you”.

So much for the humans fighting the Cold War on the “invisible front”. But the star of the show is really a building – the striking white Isokon Building or Lawn Road Flats at the Belsize Park end of Hampstead. No fewer than seven secret agents for Stalin’s Russia lived here in the 1930s and 40s – and many more sympathisers and enablers were connected to it.

MI5 had suspicions about the spy ring, but never managed to penetrate it. Indeed, Fuchs was only rumbled by the Americans in 1950 after a stint at Los Alamos in New Mexico. Under interrogation, he named Sonya as his controller – but before the connection could be unravelled, she and Jurgen beat a hasty retreat to East Berlin.

The Isokon Building, designed by Wells Coates and built in 1934, has outlived them all and most alluring it looks, too – like a giant white concrete ocean liner. A hub of bohemian left-wing activity in the late 1930s and early 40s, it housed Walter Gropius, Henry Moore, Piet Mondrian, George Orwell and any number of Freuds. Philip Harben, later the first TV celebrity chef, rustled up progressively themed dinners in the building’s communal restaurant. If Communism had ever worked in practice, it would have looked like life in the Isokon.

And who should appear in the middle of this nest of spooks but Agatha Christie. Alas, she failed to bring Poirot along to reveal the plots.

Bringing this heady, disappeared world to life with Radio 4 documentary producer Tom Alban, I went to Berlin to interview Jürgen Kuczynski’s son Thomas, just as Britain was in the throes of Brexit. Here I was, returning to the city where I’d covered the fall of Communism in 1989, just as Europe was being shaken to its foundations all over again. Life is much odder than Le Carré.


Document: Knowing Jürgen Kuczynski premieres 4pm Tuesday on Radio 4