Sounding more like a particularly unappetising punk band than stark historical fact, The Shankill Butchers remain one of the least known and least appealing quirks of the Irish Troubles. In the early 1970s they would cruise a divided Belfast in search of innocent Catholic men to unceremoniously bundle away, torture and murder. Sectarian politics provided motivation, but their drive was pure mob: cruel, callous and indiscriminate.

Art, so to speak, has revisited their story several times in recent years: as background to Chris Petit’s gassy, unsatisfying novel, The Psalm Killer; and as subject for Thaddeus O’Sullivan’s gripping but dramatically staid 1996 movie, Nothing Personal. Neither really gets to grips with the inherited horror that more properly belongs to Eion McNamee’s novel Resurrection Man - a short, serious, hallucinatory meditation on Victor Kelly, the beautiful, charismatic but ultimately psychopathic leader of the murderous Loyalist terror gang.

Scripted by the author and directed by Marc Evans, this film version should come with a warning attached: it is particularly nasty stuff. Remarkably faithful to its source, film offers little of the protection of words alone. Beatings, shootings, knifings - what is dispensed with in a line on the page spares us precious few details on screen. It was a brave decision to make a film as brutal - as flat-out sadistic - as this and it pays dividends. If you can stay with the carnage this is compelling, uncompromising viewing.

Making the implicit explicit is also, paradoxically, its only real shortcoming. The film-makers are saddled with period trappings - the clothes, haircuts, music - in a way McNamee wasn’t. It is nostalgic and distancing and has initially to work hard. Sensibly, though, it moves to place Victor (the compelling, darkly handsome Stuart Townsend), outside of time, an angel of death. In another time, another place he would have been Christopher Walken.

There is a sub-plot of sorts, about James Nesbitt’s fading reporter and his disintegrating marriage, but that ends up going nowhere and is all but abandoned by the time the end rolls around. Like the book, Resurrection Man works better when it’s a film about death than when it’s a film about character or plot. It’s here, in the police procedural, in Brenda Fricker’s mother, it’s at its weakest. McNamee is borrowing from a cinematic legacy (Victor is seen watching Cagney’s Public Enemy) that he doesn’t need.

The case remains to be argued, of course, that there is something suspect about the whole enterprise. In borrowing from Northern Ireland’s darkest episodes and wrapping them up in some of the grisliest screen trappings ever seen from a Brit-pic, the charge of exploitation has to be made. But it’s precisely that balance - between political reality and something altogether more personal and troubling - that gives Evans’ grand guignol its queasy tension. If you have the stomach, it makes for a grim and uncomfortable hour and a half.