On a Saturday morning last September Sarah [text removed], aged 14, packed a bag, hitch-hiked to Taunton - and disappeared. On a morning in February 1972, Kevin [text removed], aged 14, caught a train from Dartford to London - and disappeared. Three years ago Susan [text removed], aged just 14, took all the money she could find from her home in Cleethorpes, Lincolnshire - and disappeared. Two years later she went home - taking with her the boy she was living with. No one knows how many children run away every year. It could be as few as 2,000 or as many as 6,000. In terms of numbers, not perhaps a very serious problem; in human terms, a tragedy. Jeremy James talks to the girl who came home and to her parents; to the parents of children who have run away; to the police and welfare workers to find out where the children go - and why.