Clive Bull is Leading Britain's Conversation.
Lindsey, Whetstone: Television shows for adults are shown after the watershed - why is it called the 'watershed'?
Name: Alan, Kingstone
Qualification: Did geography at school
Answer: in geography when two adjacent rivers meet one 'sheds' into another at the meeting point. The phrase has been adopted by the media. Two audiences - adults and children - become one - just adults.