Bad Lieutenant and add in the surreal style of Trainspotting. Also, masturbation. Lots and lots of masturbation.
Like Trainspotting, Filth is based on a novel by Irvine Welsh, and like Trainspotting, it features extensive drug use and really out-there hallucinations on the part of the main character as he spirals into self-destruction. But while Ewan MacGregor found release and escape by the end of Trainspotting, James McAvoy only finds destitution and despair.
McAvoy plays Bruce, a Scottish police detective angling for a big promotion by playing his colleagues off one another. When a Japanese student is murdered by a gang, he sees the case as his chance to get the promotion and in the process, win back his wife, Carole (Shauna Robertson), who addresses the viewer directly when she goes on about how much she's looking for her husband's promotion. Bruce also has a nerdy friend (Eddie Marsan), whose wife he frequently harasses with sexually explicit phone calls. But through a combination drug use, a mental disorder, problems with the job, and other issues, Bruce begins to lose his grip on reality.
As it names indicates, Filth is, well, a filthy movie in a number of ways. As I indicated above, Bruce indulges quite a bit in self-gratification, whether it be at home or in a bathroom stall at the police station he works. He frequently snorts drugs, has a sexual relationship with the wife of one his fellow detectives (among other women), and at one point blackmails an underage witness to perform oral sex on him, which he criticizes the quality of. Appropriately, the look and feel of the film matches the subject: gray, grimy, and downright ugly.
It speaks volumes of McAvoy's skill that Bruce remains a compelling figure. It's easy to imagine the material becoming too repellant and Bruce being an unsympathetic scumbag, but McAvoy, though never soft peddling him or making him likable, holds our interest. We get voiceover narration explaining his thoughts, his strategies, even his hopes and fears, and the film is a fascinating portrait of a man losing it. There's also an interesting moral dimension to the character. At one point, Bruce tries but ultimately fails to resuscitate a man on the street. The man's widow later brings her son to the station to thank Bruce for his efforts and tells him she wants her son to grow up to be like him, and McAvoy is so good in this scene, you can see the shame silently welling up inside him
There are moments of dark humor. Bruce's thoughts reveal the personal quirks of his colleagues and how he plans to bring them down. It's hard not be amused by a character so shamelessly self-absorbed; early on a kid with a balloon flips him off, so Bruce steals the balloon and flips the kid off with both middle fingers. At an office Christmas party, Bruce and the other men photocopy pictures of their junk as part of a game, and he presses the enlarge button on the machine, so he can seduce a female co-worker (the look on her face when she realizes his size was exaggerated is priceless). That's just the kind of guy he is.
But by the end, after we've learned about Bruce's childhood trauma, the truth about the relationship with his wife, and the fact he has bipolar disorder, it's hard to keep laughing. I felt kind of bad for him. It's tempting to label the story a tragedy; after all, he is destroyed by his flaws, but a tragedy would entail some sort of catharsis for the audience, and when the movie ended, I didn't feel that. I just felt down.