No question about it, Filth could only be derived from Irvine Welsh, creator of Trainspotting, though Jon S Baird‘s cynical homage tones down excess Scottish cultural and linguistic traits, but not by much; compromises in this tale are few and far between.

The fast-moving stylised roller coaster ride depicting the seamy foul-mouthed underbelly of Scottish life is uniquely Welsh, this example taking the corrupt, ambitious, amoral if not immoral foul-mouthed Machiavellian Scottish Police Sergeant Bruce Robertson, intent on getting promoted by “playing the game” – trashing his competitors for the role of Detective Inspector while riding a mad roller coaster of fags, booze, drugs and hookers, not to mention shagging the wives of friends and colleagues for good measure.  Robertson’s idea of kicks is manipulating anyone he can for the hell of it, because he can.  By any standards, this is a thoroughly nasty, despicable man, though as it turns out he also has a weak and vulnerable side which does not – cannot – exonerate his many sins but does at least go some way towards providing a rationale for how he became such a monster.

At one level the malevolent and misanthropic cop can be taken as a metaphor for all that is mad, bad and dangerous to know about policing in Scotland and elsewhere, though equally it depicts the gradual crumbling of a self-assured egomaniac deep into the bottomless pit of insanity and eventually suicide, thus saying much about the treatment of mental illnesses in Scottish society.  Robertson’s hallucinations see him with the face of a pig, and also offer visions of his long-dead younger brother; both facets of a conscience crammed with guilt, the flip side of his public persona.  Small wonder we find out that his increasingly bizarre psychiatrist has diagnosed bipolar disorder and prescribed medication which Robertson leaves untaken upon his shelf.  Oh, and a spell of transvestism, allegedly to get closer to his wife, but with an unfortunate impact.

Yes, this is dark, bleak and vivid comedy of sorts but offers the depth to be interpreted at different levels, always the sign of a fine source material, coupled with actors capable of providing the level of intensity and clarity required in such a venture, not least taken well out of their comfort zone.  According to the DVD box, FHM describe his portrayal of Robertson as James McAvoy‘s “performance of a lifetime” – and while it is very different to anything else I’ve seen him in, you would find it hard to argue with the sentiment seeing his deep baggy-eyed  glare, vicious sneer and cynical utterances, which changes over time to a pitiful grief-stricken primal scream from the depths of his soulless void right at the end.  That look will stay with me for a long time.

Equally beyond the usual limitations applied to him is Jamie Bell (AKA Billy Elliot) as the young ingenue who learns fast, though Jim Broadbent is such a versatile actor he can take the role of a whacky psychiatrist Dr Rossi in a series of dream-scape rants well within his stride.  Look also for a bizarre cameo from David Soul as a punter, sending himself up by singing Soul’s hit Silver Lady, and the wonderful John Sessions as Robertson’s reluctant boss. In fact, the film is imbued with a fair number of surrealistic comic interludes that could easily provoke anxiety in viewers of a nervous disposition.

In fact, everywhere you look there are great actors, certainly a telling tribute to the pulling power of Messrs Welsh and Baird. One such is an actor I’ve long admired, Eddie Marsan, here the naive well-meaning buddy to Robertson, the nearest thing he has to a friend.  Alas, Clifford is so easily exploited directly and through his sex-starved wife Bunty (Shirley Henderson), but that is what Robertson does to his friends, and indeed the wife Carole (Shauna Macdonald) who remains loyal through (almost) all his shenanigans, because to her power is the greatest aphrodisiac.  When he loses power, he loses her.

All of which reminds me of another key component of Filth:  While Robertson may use and exploit weak and vulnerable women for sex, many of the women in this picture come out as far more robust than Robertson, each in a subtly different way.  The equivalent film say 40 years ago would not have given the women any saving graces – they would have been victims of the camera just as some are victims of Robertson.  There is not a bad performance among them, though I was particularly impressed by Imogen Poots, who endows her ambitious copper, Amanda Drummond, with three dimensions and an unexpected seam of compassion.

I’d struggle to describe this as an enjoyable movie, and indeed the inky blackness at its heart may have contributed to an indifferent return from the box office.  This is not to say it is a bad movie at all, but not one people will remember or view again with fondness and glowing heart.  A shame, because in my humble opinion it deserves greater analysis to deconstruct its more salient comments and Welsh’s cunning subtext.  It’s a box of tricks, and trust me when I say Welsh has more tricks up his sleeve than many writers achieve in a lifetime.