In a cafe in the heart of Birmingham, a woman and man sit opposite one another.

Their deep in discussion as the world passes by outside the window.

It is the summer of 1942 and the war is now truly a world war.

From North Africa to the Pacific Islands, fighting rages.

Germany and Britain are fire bombing each other's cities

in an effort to destroy their enemy's war machines

and break the will of their peoples.

But in this quiet cafe, it's just another sleepy afternoon.

The couple discuss books, films and of course the war.

They enjoy each other's company.

She finds him tactful, thoughtful and cultured.

She is someone he can discuss his feelings with.

But they haven't come here for camaraderie or romance.

He slips her a slim cardboard file which she calmly places into her bag.

They finish their tea and get up to leave.

As they step into the street, they park cordially and go their separate ways.

The atomic spy, Klaus Fuchs, has just met his new handler, My Great Khan,

who he knows simply as Sonja.

The file he has just transferred to her contains dozens of pages

of top secret documents.

Secrets with the power to change the world.

From the BBC World Service, I'm Rosa Ellis.

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