The 1933 memoir of Vera Brittain (the first and best-known volume of a trilogy) is widely seen as a landmark work. An early classic of feminism, it depicts its author's defiant determination to go to university and become a writer - an aspiration dismissed as bluestocking and unladylike. More groundbreaking still was her argument - dredged up from the grief of losing her fiance and her brother in France's killing fields - that pacifism was a feminist issue.
This film adaptation, released during centenary commemorations of the war that was supposed to end war, might have adopted the starchy, reverential tone that marred the 1970s BBC TV series. But it avoids all the formulaic pieties: it is an exquisite piece of work that shimmers with authentic emotion.
The rushed and traumatic horror of station platform farewells; the grey, hollow-eyed deadness of men on leave who cannot comprehend, much less talk about, what they have seen; the electric thrill of a lover's touch under the eye of a chaperone: time and again the film, alive to the emotional undercurrents of each scene, evokes with hair-raising precision the human reality of its characters' lives.
Swedish actress Vikander (A Royal Affair), in a role initially intended for Saoirse Ronan, sports a superb English accent as she finds the steel in a character who begins as a slightly petulant tomboy. When she accepts a proposal of marriage, or better still, when she realises the wedding's not happening - these are standout moments of a performance of sustained brilliance from an actress with a dazzling future.
Barely less creditworthy is the work of the quartet of men (including Harington and Egerton as Vera's fiance Roland and brother Edward respectively) who chart the steady descent of men who marched away: "How many generations get the chance to be involved in something like this?" Roland asks excitedly as he signs up. Dramatic irony doesn't come more bitter than that.
