Happy birthday to Radio 4 pips
5 February 2014 Last updated at 09:50 GMT
The radio 'time pips', still heard on outlets such as BBC Radio 4 and BBC World Service radio, are 90 years old.
To celebrate, BBC Radio 4's Today programme played a special happy birthday version of the pips, and spoke to former BBC announcer Charles Lister.
First broadcast on BBC Radio 4's Today programme on Wednesday 5 February 2014.