In June, 1940, the Times of London published a letter written by a British bomber pilot to his mother. It created a sensation in England and was widely distributed in a pamphlet. Michael Powell's short film version of it is simple: On a frosty morning in a small English village, a postman slips a letter through the mail slot of a typical home. A woman, whose face is never quite clearly seen, picks it up and opens it as she retires upstairs, followed by a dog. The woman goes into a room, the sign on the door of which indicates it belongs to her son. She sits down and begins to read. The voice of John Gielgud narrates the contents of the letter, during which the woman's son tells her that his role in the war has been in important, that his death had not been in vain, and that she should not grieve for him. During the narration, the camera moves around the room, taking in some of his personal belongings, including many books and pictures that relate to heroism and English tradition. At the end, as the letter speaks of higher things, the camera pans out of the window and up into the sky, ending with a superimposed, cloud-like shot of the RAF wings insignia.
~ Craig Butler, All Movie Guide