In 1948, filming began on a post-war thriller that would become one of the greatest British movies of all time.

Directed by Sir Carol Reed, the film captured the atmosphere of a divided, ruined Vienna.

But much of its lasting power lies with Orson Welles, whose magnetic, menacing turn as Harry Lime stole the show - despite his limited screen time and reputation for being famously hard to pin down.

Phil Jones speaks to production assistant Angela Allen about the film that became legend.

Eye-witness accounts brought to life by archive. Witness History is for those fascinated by the past. We take you to the events that have shaped our world through the eyes of the people who were there. For nine minutes every day, we take you back in time and all over the world, to examine wars, coups, scientific discoveries, cultural moments and much more. Recent episodes explore everything from the death of Adolf Hitler, the first spacewalk and the making of the movie Jaws, to celebrity tortoise Lonesome George, the Kobe earthquake and the invention of superglue. We look at the lives of some of the most famous leaders, artists, scientists and personalities in history, including: Eva Peron – Argentina’s Evita; President Ronald Reagan and his famous ‘tear down this wall’ speech; Thomas Keneally on why he wrote Schindler’s List; and Jacques Derrida, France’s ‘rock star’ philosopher. You can learn all about fascinating and surprising stories, such as the civil rights swimming protest; the disastrous D-Day rehearsal; and the death of one of the world’s oldest languages.

(Photo: Harry Lime, played by Orson Welles in The Third Man. Credit: Corbis via Getty Images)