Frank McGuinness’s iconic war play, Observe the Sons of Ulster Marching Towards the Somme, is at Cambridge Arts Theatre from October 4 to 8. The play is in remembrance of July 1, 1916, the first day of the Battle of the Somme when thousands of men were killed. The play features on eight ordinary Irishmen involved in the slaughter. We see their conflicts as they fight a fight that isn’t theirs. These heroes are all the more real for being human and flawed.