Ursula Kuczynski, also known by many other names - probably most famously ‘Agent Sonya’ - was a Jewish German activist who spied for the Soviet Union during the 1930s and 1940s, and was most well known for being the handler of nuclear scientist, Klaus Fuchs.

In this podcast and radio series, The Bomb season two, Rosa sets out to discover how her great aunt Ursula and Klaus Fuchs came to cross paths, why they risked their lives, and how their partnership changed the course of history.

It follows on from the success of The Bomb season one, which told the story of the scientist who tried to stop the first atomic bomb that dropped on Hiroshima.

Season two focuses on events in the 1940s regarding Klaus Fuchs, a German emigré, nuclear scientist and Soviet spy who worked on the British atomic bomb project, and fellow Soviet spy, Ursula Kuczynski, his handler.

Who was Fuchs, the man who stole from Britain and the US, and gave Russian intelligence the theoretical outline for creating the atomic bomb and the initial drafts for its development? What role did Ursula Kuczynski play in facilitating him? And how did Fuchs, a prodigious young talent at the beginning of his promising academic career, evolve into a fully committed Soviet spy, with access to one of the most secretive areas of science and Britain’s national defence?

Listen to The Bomb season two trailer here

The first episode of the podcast will be released on 9 July and weekly after that. You can listen on BBC Sounds or wherever you get your podcasts. The first episode will also air on BBC World Service Radio on 9 July, and will be broadcast weekly.

The Bomb season two is a BBC World Service production, produced by Zak Brophy. It is presented by Rosa Ellis. It is executive produced by Glyn Tansley and commissioned by Simon Pitts.

The original music is composed by Trevor Gureckis. The sound design is by Tim Nielsen at Skywalker Sound. It is mixed by Eloise Whitmore of Naked Productions. The story editor is the writer and audio producer, Emma Harding.