In 1917, the war is in its darkest phase. Everyone knows victory can only come at a long, slow, and painful cost. So many lives have been lost that now men previously exempted from military service – because of their age or because their jobs were considered vital to the war effort – are called up. We hear the stories of three of them: the black Glasgow shipbuilder Arthur Roberts, sent into the Battle of Passchendaele; Duff Cooper, the dashing and debonair lover of Lady Diana Manners, the daughter of the Duke of Rutland; and Londoner Ted Poole, just 18 and the last of his fathers’ sons left alive.

• Adrian Scarborough
• Claire Foy
• Olivia Colman