There isn’t a layer of emotional resonance within which Sam Mendes’ latest feature does not excel. A First World War thriller, boasting the dramatic surety Mendes nailed in Skyfall and all but lost in Spectre, 1917 quickly takes hostage of the heart and refuses release. It is electric, devastating and charged with a profound sense for the absolute horror of warfare. That the story comes from the original experience of Mendes’ own grandfather on the Western Front is paramount. This one matters to him sincerely.