Wholly unprepared for what was the world's first broadcast war, the BBC fended off complete government takeover and emerged a trusted global news source, transmitting in 47 languages. Using a wealth of preserved recordings and previously unseen documents, Jonathan Dimbleby uncovers the compelling story of how the BBC went into battle - against Hitler and Whitehall's ministers - and its part in the social revolution the war provoked.

The conclusion of the two-part documentary examines the impact the BBC's broadcasts had on the war zone. Jonathan Dimbleby looks at how it provided a counterpoint to Nazi propaganda and a source of coded information for resistance groups. He also discusses how BBC correspondents were embedded with military units during D-Day, and recalls his own father's reporting on the liberation of Belsen and the fall of Berlin.