The Clangers, which returns to the BBC today, are the latest salvo in a fierce battle for younger viewers between the BBC, Sky, Netflix and beyond, stretching from the TV in the living room to the smartphone in your hand. Amazon and Netflix have each turned to original production to supplement the thousands of hours of acquired material on their on-demand services. Amazon’s latest six children’s pilots include Lily the Unicorn, an animated adventure from the Muppets creator the Jim Henson Company.