In this week's exploration into BBCtv's film and videotape library Chris Serle discovers - childhood. Find out what it was like to go Back to School in 1949, and in Special Enquiry how cold a 1955 classroom could get. Joyce Grenfell as the classic school mistress explains to George that we don't do that, while Richard Dimbleby finds out what else we don't do at Marlborough College, in Portrait of a Public School, 1954. There's early children's viewing with Rag, Tag and Bobtail, Mr Pastry and Whacko, with a whistle in the dark from the Clangers. There's star guest Richard Stilgoe with a feast of memories of childhood, not forgetting Billy Bunter of Greyfriars with a feast of his own. Assistant producers KINA MURRAY. TONY MUCKLOW Director NIGEL HAUNCH Series producer ALBERT BARBER