Loosely based on the real life crimes of American serial killer Henry Lee Lucas, John McNaughton's haunting film is a grim journey into the life of its twisted subject that refuses to moralise or judge.

Which is why "Henry: Portrait of a Serial Killer" caused such controversy when it was first released in 1986, with the British Board of Film Classification initially refusing to release it at all after their American equivalent, the MPAA, claimed that they "wouldn't know where to begin cutting".

It's hardly surprising the censors felt so powerless. After all, the real impact of the film doesn't reside in extreme imagery or sexual explicitness, but in its atmosphere of utter desolation. Which is why the additional 60 seconds of footage restored in this uncut version add little to the overall effect.

Arriving in Chicago, Henry (Michael Rooker, in what is undoubtedly the finest performance of his patchy career), moves in with ex-con acquaintance Otis (Tom Towles) and starts schooling him in the ways of the serial killer.

Yet while Otis savours each kill, whooping up the violence like a drunken redneck, Henry approaches his slayings without a single shred of emotion.

It's exactly this amoral nonchalance that makes Henry (both the film and the man) so disturbing. Rooker's dead-eyed impassivity leaves us in no doubt that he's incapable of registering the impact of his actions, while McNaughton's documentary style deprives the audience of any moral centre, or sense of release from this nihilistic world.

Whether read as a tacit indictment of the self-centred brutality of the Reagan years, or simply as a "portrait of a serial killer", this is an incredibly powerful, troubling film which, next to Jim Van Bebber's brutal short "Roadkill: The Last Days of John Martin", is quite possibly the most harrowing real-life serial killer movie ever made.