In what year was the telephone speaking clock introduced in the UK?

In the United Kingdom, the speaking clock can be reached by dialling 123 on a BT phone line; the number may vary on other networks.

A speaking clock service was first introduced in the United Kingdom on July 24, 1936. The mechanism used was an array of motors, glass discs, photocells and valves which took up the floorspace of a small room. The voice was that of London telephonist Ethel Jane Cain, who had won a prize of 10 guineas in a competition to find the right voice. Cain's voice was recorded optically onto the glass disks in a similar way to a film soundtrack. The service was obtained by dialling the letters TIM (846) on a dial telephone, and hence the service was often colloquially referred to as "Tim". However this code was only used in the telephone systems of the cities of London, Birmingham, Edinburgh, Glasgow, Liverpool and Manchester. Other areas initially dialled 952 but with the introduction of Subscriber Trunk Dialling it was changed to 80 and later 8081 as more 'recorded services' were introduced and was standardised to 123 by the early 1990s.