In this bank holiday edition of the programme Helen Skelton looks at how the British countryside has shaped childhoods down the ages and been everything from playground to classroom to sports field. She travels to Northamptonshire to rediscover the works of one-time children's favourite author, Dennis Watkins Pitchford. Better known as BB, he was as big as Enid Blyton in his day. Book in hand, Helen explores the countryside that features in BB's stories. While she's there she looks back at some of the best films on Countryfile that have featured kids and childhood