Bong! Big Ben is striking the hours. Microphones installed above the bell record the sound live for some BBC news bulletins. (Until the present system arrived in 1924, radio announcers had to play the chimes on handbells.) Only one of today’s four microphones is actually working. Don’t you love the BBC?

I know this because I’ve just visited the clock tower, a deeply satisfying experience. We’d passed the tower often enough, yet its internal workings were a mystery. George Airy, the Astronomer Royal, insisted that the clock should be accurate to a second a day: a seemingly insuperable challenge to the clockmakers.

Enter Edmund Beckett Denison MP, a ‘zealous but unpopular, self-accredited expert on clocks’ and other things, the sort of pompous know-all who, annoyingly, is generally right. His clock was a marvel, but his insistence on using too heavy a hammer cracked the first bell. Big Ben also cracked for the same reason, but could soldier on when rotated. Bong! We had our earplugs in place when it rang.

Why Big Ben? I’d always thought it was named after the MP Sir Benjamin Hall. According to the Whitechapel Bell foundry, a more likely contender is heavyweight prizefighter Benjamin Caunt.