With its distant echoes of Laura, Postmark for Danger (a.k.a. Portrait of Alison) survives as one of the few English crime dramas of the post-war period with some of the grit and menace of American film noir. (Americans, plus one Canadian, make up the principal cast. But the film betrays its British provenance with its assumption of the utter incorruptibility of the London police - a notion that wouldn't pass muster on the west side of the Atlantic - as well as with its the-butler-did-it resolution.)
Robert Beatty, a commercial artist, hears some bad news from his pilot-for-hire brother (William Sylvester): a third brother has died in a fiery car crash in Italy, along with a young actress he had met. Then strange things begin to happen: The police grow interested in a postcard his dead brother may have sent him, as do elements of the underworld; and the father of the actress commissions him to paint a portrait, working from a photograph, of his daughter. Next, he returns to find the portrait vandalized, the photograph missing, and his favorite model dead in his bedroom, wearing the gown in the painting. He becomes the prime suspect in the murder when no evidence can be found to support his wild claims - until the supposedly dead actress (Terry Moore) shows up at his door.
At the end of the day, Postmark for Danger settles down into a tidy police procedural about a ring of diamond smugglers. But for much of its course it unfurls in a tantalizing mist of eerie and unlikely coincidences, many of them centering on the word `nightingale.' Credit should probably go to director Guy Green, who started out as a cinematographer (he shot David Lean's Great Expectations). It's an enjoyable if minor entry, albeit one with just a little bit extra.