On Good Friday 1930, the journalists on BBC radio news did not know what to put in the evening bulletin. The country was on holiday. The world economy appeared to be recovering after the Wall Street Crash of 1929. Few guessed that the revival was a suckers’ rally that heralded a global depression. Europe was quiet — Adolf Hitler was still an obscure opposition politician — and although Britain ruled a great empire, nothing much seemed to be happening there either.

Stumped by a slow news day, the BBC delivered the most honest broadcast in the history of journalism. “Ladies and gentlemen, there is no news tonight,” proclaimed the announcer. “So here is some music.” They then proceeded to play 10 minutes of piano music for the listeners.