As Steven Spielberg's movie version of War Horse arrives on UK cinema screens, the author of the novel on which it is based is among the contributors to How to Write. Michael Morpurgo reveals the sources of his inspiration and the techniques he uses to 'just get the stupid thing down on paper'. Philip Pullman, writer of the His Dark Materials trilogy, discusses the need for discipline, the importance of memory, and how it is crucial to stand inside a scene and imagine what is seen and not seen. Also taking part are poets Caroline Bird and Kate Clanchy, and novelists Rebecca Abrams and Charles Cummins. They are among a group of top authors gathered at Broughton Castle in Oxfordshire to share the secrets of creative writing with almost 400 young people