Charlie Mackesy's poignant story of friendship: The Boy, The Mole, The Fox and the bathtub

Charlie Mackesy's extraordinary journey from unknown artist to best-selling author, self-help guru and now film-maker with his beautiful animated film The Boy, The Mole, The Fox and The Horse, airing later today and tomorrow morning on television, began with a conversation with his friend Bear Grylls about bravery.