In the summer of 1916, the First World War's bloodiest battle was fought around the river Somme in northern France. It lasted three months and there were thousands of casualties on both British and Commonwealth, and German sides. For the first time ever, British cameramen were allowed to the Western Front to film its opening stages. The edited footage that they came back with became a box office smash, and has been shaping our view of that bloody conflict ever since. Robert Hall tells the story of one of those men, Geoffrey Malins.