Filth is based on the book of the same name by Irvine Welsh who also wrote Trainspotting. Armed with this information you can probably guess some of the dominant elements of the film: Rampant drug abuse, check; alcoholism, check; copious amounts of, lets call it “unusual”, sex, check; lots of swearing, check; some pretty freaky hallucinations, check. Oh and it is set in Edinburgh, obviously.
This time, instead of the junkies and criminals of Trainspotting, the main characters of this story are police officers as the name “Filth” implies. Bruce “Robbo” Robertson, played by James McAvoy, is a formerly brilliant Detective Sergeant with the Edinburgh police. He seems to have fallen on hard times though. Although at first he keeps up a façade of his usual self with his colleagues, his behaviour soon begins to deteriorate and even his more dimwitted colleagues start to have concerns about him.
Bruce’s wife and daughter have mysteriously disappeared (mysteriously to the viewer and also to Bruce who claims not to know what happened) and he seems to have been given the ultimatum that he needs to get a promotion at work in order to win them back. Fortunately there is a Detective Inspector post open and Bruce seems to be the favourite for the job. When a Japanese student is killed by a group of punks it seems that all Bruce will need to do to secure his coveted promotion and return to his happy family life is solve the case and bring the criminals to justice.
However, instead of putting any real effort into solving the murder, Bruce prefers to spend his time undermining and discrediting anyone who he sees as a rival in the promotion race while also taking as many illegal drugs and having sex with as many people as he can as his personal and professional lives spiral increasingly out of control.
Bruce has hallucinations which are infrequent at first but become more frequent and increasingly disturbing as the story progresses. Annoyingly the film usually introduces these with jump-scare stings in the soundtrack which I feel actually diminishes their impact. He is also haunted by visions of an apparently dead young boy and of his missing wife and daughter. Bruce’s back story is quite cleverly introduced via more extensive sequences which appear to be hallucinations where he discusses his situation with his psychiatrist Dr. Rossi played brilliantly by Jim Broadbent. Dr. Rossi is initially a benevolent if distant figure who becomes increasingly aggressive and frightening as Bruce’s condition worsens.
Despite being obsessed about the promotion, Bruce spends a lot of the film on activities outside work. He is conducting several affairs and also spends a lot of time at his masonic lodge either sucking up to or bullying and robbing his fellow brothers. He abandons the investigation to take a fellow brother to Europe for a weekend of booze, drugs and hookers.
The style of the film is deliberately disjointed reflecting the fractured nature of Bruce’s mind. The style fits with the message that the film is trying to convey so it doesn’t feel forced like it might in a different film. Given the amount of time Bruce spends drunk or stoned on legal and illegal drugs it seems quite natural that he should wake up with chunks of his life missing.
McAvoy is great as the lead character and convincingly portrays someone who is struggling with demons past and present. Although he is an unpleasant character and is horrible to almost everyone he meets throughout the film you start to feel sympathy for him as some of the events leading up to his current situation are revealed and you start to root for him as the film progresses. Many of the other supporting characters though are pretty superficial. Much of this is probably due to the film being narrated almost exclusively from Bruce’s perspective so you really only get his skewed view of their character.