How they put Charlie Chaplin's silent comedy on the radio

I've been reading David Robinson's biography of Charlie Chaplin. It's an amazing tale.

Chaplin makes his name on the London stage in the 1900s. He goes to the USA as a stage performer. Somebody tells him that his pantomime style will work in pictures, which are the new new thing.

He starts making movies in Hollywood just as the First World War is breaking out in Europe. By the time it's over he's the biggest superstar in the biggest business in the history of entertainment.

He's the most famous man in the world. Because he dealt in mime rather than language he was famous in a way we simply can't imagine today.

When radio, another new new thing, comes along in 1920 he's beside himself with nerves at the thought of speaking into the live microphone.

When The Gold Rush opens in London in 1925, the BBC, casting around for new uses for the new medium, broadcasts ten minutes of the sound of the film's audience at the Tivoli in the Strand laughing at Chaplin's performance.