Tomorrow marks the 80th anniversary of the catastrophic opening day of the Battle of the Somme. 19,000 men died and 40,000 were injured: the largest ever one-day loss by the British army. Today, the battle sits at the edge of living memory but refuses to slip quietly into the past. Writers Geoff Dyer and John Berger go in search of what is left of the Great War and try to penetrate the spell that it continues to cast.
Producer Roger Elsgood