Filth, review - Telegraph Dir: Jon S. Baird; Starring: James McAvoy, Imogen Poots, Eddie Marsan, Jamie Bell, Jim Broadbent, Shirley Henderson, Kate Dickie, Martin Compston. 18 cert, 97 min. I loved every minute of Filth, and couldn't have stomached another second of it. That reaction might sound paradoxical unless you already know that the film, which was written and directed by Jon S. Baird, is an adaptation of the third novel by Irvine Welsh, the author of Trainspotting and a practiced unsettler of alimentary tracts. Come to think of it, "alimentary tract" would be a good way to describe Welsh's original book. Published in 1998, it told the bile-black tale of Bruce Robertson, an Edinburgh police detective and enthusiastic racist, homophobe, drug-abuser and woman-hater who makes life a waking hell for anyone in his blast radius. Of the novel's many charms, some of the more delightful were the occasional interruptions of Robertson's narration by the merry natterings of his tapeworm, which were splurged across the page in bold, sans-serif type. In Baird's picture, the tapeworm has been sidelined to a brief cameo and the plotting is tidier, but the humans are no less monstrous. Robertson himself is played by James McAvoy; his eyes hooded, his complexion Gollum-like, his beard a tone and texture that suggests it may have been recently used to scour out a deep-fat fryer. McAvoy, on his best form since Atonement, performs what might be the most dangerous balancing act by a leading man this year, teetering crazily between repugnant and pathetic without ever passing through likeable, and yet somehow never loses you in the process. Although he is supposed to be investigating the murder of a foreign student, Robertson spends most of the picture engaged in explicit extramarital sex, alcohol and drug abuse, and "The Games," which is his term for casual psychological warfare. The victims are his colleagues in the Lothian and Borders Police (fun supporting roles for Jamie Bell, Imogen Poots and others) and a wee, sleekit, cow'rin, tim'rous beastie from the Masonic Lodge called Clifford (Eddie Marsan), who comes uproariously unstuck with Robertson on a lads" weekend in Hamburg. Elements of the Bad Lieutenants, both Abel Ferrara's and Werner Herzog's, can be spotted in Robertson's nihilistic antics, although the biggest filmic debt here is to Malcolm McDowell's Alex DeLarge. Baird and McAvoy both draw avidly on Stanley Kubrick's A Clockwork Orange, but without the lightness of touch shown by Danny Boyle when he made similar borrowings in his adaptation of Trainspotting. Seventeen years on, Boyle's film still plays like a firework rammed up the exhaust pipe of British cinema. Filth feels like more of a cult concern than a cultural one, but covers you in its sticky fingerprints just the same.