You know the story. The abduction of Helen. The wooden horse. The fall of Troy.Simon Armitage’s new play is a vivid re-engineering of Homer and Virgil, a meditation on ‘own’ and ‘other’, an unblinkered look at the costs and sorrows of war. In truth, a play about war (rather than a lion hunt, say, another ancient theme) will always be of the moment: Achilles mutilating Hector’s corpse; a British soldier giving a thumbs-up over the body of a dead insurgent.