The show took its name from the message (frequently seen on the TV screen in those days) which was displayed when there was a problem with transmission.
It included early appearances of many actors and comedians who later became famous, such as Denise Coffey and David Jason. Eric Idle, Terry Jones, and Michael Palin later became members of the hugely successful Monty Python comedy troupe. Although, originally conceived as a children's programme, it quickly acquired a cult crossover following amongst many adults, including future Pythons John Cleese and Graham Chapman