Little countdown noise every hour in BMW 520 M Sport (09)?

[bowden_green]

My dad has a BMW 520 M Sport (registered 2009), and every hour there is a little countdown timer, which sounds very familiar to the BBC pips that Radio 1 often use. I was just wondering if this is a standard feature or whether it shouldn't actually be happening. We had a 5 Series touring that didn't have this, and were a little worried thinking it was a bomb or something! Thanks.