24 July 2016 Last updated at 00:02 BST
The talking clock was originally designed for people who did not have a watch or clock to hand.
Over its 80-year lifetime four people have voiced the talking clock; Ethel Jane Cain, Pat Simmons, Brian Cobby and most recently, Sara Mendes da Costa.
On 24 July 1936, the talking clock spoke for the first time.