Battle of the Somme

It was the first truly industrial battle, and yet veterans recall hearing skylarks singing just before the whistles blew at the Battle of the Somme. A century later, these birds remain, singing long after the carnage came to an end. Paul Reed is a military historian and author specialising in the First and Second World Wars. He has been conducting battlefield tours for over a quarter of a century. In this episode from the centenary he spoke to Dan Snow.