Two-part series which tells the story of children's outdoor games in 20th-century Britain begins by looking at British children at play between the 1900s and the mid-1950s. It is a journey into a secret world of adventure and imagination that blossomed in the nation's streets, back alleys and playgrounds. The children's songs and games were passed down from one generation to the next and remain an abiding memory for most grown-ups. Playing on the streets was the defining feature of a working class childhood. But the freedom they enjoyed meant they often got into trouble; none more so than the tribal gangs of boys who named themselves after the places where they lived. The programme highlights how children's play varied between city and country, between the different social classes and between boys and girls.