It's 3 a.m. on Monday the 10th of September 1949. In the North London home of Michael

Perrin, director of Britain's Atomic Energy Program, the telephone rings. Perrin

is startled from his dreams. Still half asleep, he rolls out of bed and grabs the phone. A voice

on the line delivers an urgent message. The Americans, what could they want? His mind races.

He finds no answers but he knows it must be serious. He rushes to get dressed and hurries

out of the door into the dark night. He jumped in a taxi, made the 15 minute ride down

to the middle of London, went to the embassy where he was hustled into the secure communications

room there by the U.S. State Department officials. There were several coded telek's messages

that had come that evening from the Pentagon that said the U.S. Air Force, using especially

equipped planes, had detected radiation in the atmosphere. There can only really be one

explanation. Four years after atomic bombs have devastated the Japanese cities, Hiroshima

and Nagasaki, the Soviets have exploded an atomic bomb of their own. British and American

scientists have assured their governments that Russia is three or more years away from

getting the bomb. But this news completely reshapes the post-war landscape. A Russian bomb challenges

American global supremacy. And for the Brits, it could mean obliteration. Moscow is only 1500

miles from London. How can this have happened?

On the BBC World Service, I'm Rosarellis and this is Season 2 of the Bomb. Episode 1, A Grave Matter.

In this quiet graveyard on the outskirts of Berlin, there's a headstone. It's small, made

of pinkish granite. It's engraved with blocked capital letters, but no epitaph, just

a simple name and date. There's no hint at the historical significance of the man buried

here. Klaus Fuchs. In life, Fuchs was now standing mathematician and theoretical physicist.

When he died, standing at his funeral here in 1988, there was a KGB agent. His name, Vladimir

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