Drowned out

SIR – I wanted to hear what Rabbi Jonathan Sacks had to say on Radio 4, but there was an annoying tinkle going on in the background. I switched him off. Why this background noise when anyone speaks on radio or television?

Jim Hendrick

Williton, Somerset

SIR – I turned on Radio 4’s Today yesterday to hear the presenter saying: “Well, thank you for explaining dark matter so clearly.” What did I miss?

Ruth Becker

Aylesbury, Buckinghamshire