“Testament of Youth” is heartbreaking because of Vera’s ultimately inspired anti-war comment pleading for no more wars. Watching, one knows, of course, of all the ensuing wars, including World War II, and the slaughter in Korea, Vietnam, Iraq and Afghanistan.

Director James Kent, working from Juliette Towhidi's screenplay adaptation of Brittain’s memoir, adheres mostly to a pensive tone, save from a few passionate moments , mainly those in which Brittain expresses her views on womanhood and war. This gives the film an an unusual ambience of maturity, despite the youth in the title.

The film’s greatest asset is the remarkable, moving performance by Swedish actress Alicia Vikander as British Vera Brittain. I had greatly admired her in the Danish film “A Royal Affair,” set in the late 18th century, as Queen Caroline Mathilda, who journeyed from her native England to marry Denmark’s King Christian VII. Therefore, it doesn’t surprise me that she gives such an accomplished performance as Brittain.

Vikander’s effectiveness becomes apparent early when she invokes her sense of feminist independence and tells her parents of her decision never to marry and her determination to go to Oxford rather than follow a traditional life of marriage and children. She rejects a piano that her father buys her a s gift, pointing out that all that money could go for tuition at Oxford. Her father subsequently gives in to her wishes, and she does go to Oxford, where she is mentored by the stern but understanding Miss Lorimer, played by Miranda Richardson.

The film makes a point of young men who feel they must not shirk their sense of duty and obligation by enlisting in the military. They fall suckers to the prevailing illusion in England that the war with Germany will be short. Director Kent includes scenes that suggest the battlefield horror without turning this into an action film. The disaster is reflected mainly through the sense of loss at home over the long published casualty lists, and in particular the personal losses that Vera suffers. Kit Harrington is excellent as Roland, with whom Vera falls in love, and Taron Egerton is fine as Vera’s brother Edward, as is Colin Morgan as Edward’s school chum Victor.

Vera acquires her own sense of duty and leaves Oxford to become a nurse and deals with the war victims. She is startled to see the suffering, and does her best to administer help and alleviate pain. Kent includes one memorable overhead shot of a vast layout of victims, a scene that tugs at the heart.