Directed by Oren Moverman. Starring Ben Foster, Woody Harrelson, Samantha Morton, Jena Malone, Steve Buscemi 15A cert, limited release, 110 min

It may have taken two years to open here, but Oren Moverman's well-researched drama exposes the unhappy truths of war on the home front, writes DONALD CLARKE

WHERE HAS this been hiding? Much has been made of the fact that The Beaverhas been lurking on the shelf for a suspiciously long period. When compared with Oren Moverman's debut, that Mel Gibson drama appears, however, to have been flung hurriedly into unprepared cinemas. Released in the US during 2009, the picture secured Woody Harrelson a best supporting actor nomination at the ceremony before last.

Fear not. The film turns out be a very powerful – if occasionally rather theatrical – treatment of a sensitive subject. Ben Foster, hitherto a strong supporting player in indie fare, turns up as Will Montgomery, a returning Iraq veteran unwillingly pressed into the delicately named “bereavement notification” unit. These are the officers who are detailed to inform next of kin that their loved ones have been killed abroad.

Harrelson is characteristically earthy as his superior, a veteran of the first Gulf War, who insists that they play strictly by the rulebook. No physical contact should be made with the bereaved. If the next of kin is not at home they must immediately turn on their heels. The announcement adheres to a firm template. (Moverman, writer of I'm Not Thereand Jesus' Son, has clearly done his research.)

In a peculiar way, the notifications play like action sequences in this original take on the war movie. Tension simmers as the two men approach each doorway. Contrasting explosions of emotion then batter the screen. Some are angry. Others are disbelieving. A few manage sympathy for the men carrying out their unenviable duty.

Shooting with a mobile camera, Moverman skilfully teases out the developing relationship between the angry young man and his more resigned, cynical boss. But the film is at its best when probing the ways ordinary citizens deal with extraordinary trauma.

Sometimes their reactions feel a little overworked and poetic. Would a father, upon hearing his son has been killed, really point to a tree and remark that it is the same age as his late child? For the most part, however, the picture rings true. As ever, Samantha Morton, playing a bereaved parent to whom Will warms, brings uneasy degrees of authenticity to the picture.

Her grim resignation helps press home unhappy truths about aspects of the war that the military establishment prefers not to publicise. The Messengeris a gruelling experience, but it's well worth enduring.