Let's be entirely fair here, James McAvoy has a habit of playing the nice guy in films. Ever since that appearance in Atonement, it's hard to ever imagine he could be a nasty person. Even with the roles where he has played someone with questionable motives, he still manages to come away from the project without even a hint of a bad word against his name.

However, there can only be so many good guy roles an actor could play before he can begin to feel like his acting abilities are not being stretched to their full potential. If, as an actor you are looking to create a bit of a stir, there really is no need to look anywhere further than Irvine Welsh, he of Trainspotting fame. You can almost guarantee most of the material will offend a multitude of people, but you can also be certain that the general public will never box you into a corner ever again.

McAvoy must have been aware of this public perception. In an interview just last week, he proclaimed that he wouldn't be surprised if people left the cinema during Filth, and worry not, it can, on occasion, give you reason to want to leave.

Based on the book by the same name, Filth follows the life of Bruce Robertson, a wayward cop who spends most of his time trying to turn everyone around him against each other in order to get his prized promotion. Bruce claims he used to be a nice guy but a brief snapshot of his life proves that he may not be the nicest of people.

Besides his drug and drink binges, Bruce continues to weave a web of lies and deceit, which he claims is part of an attempt to bring his wife and child home. However, he soon realises that those he has wronged will soon outweigh his supposed friends, and with a fragile state of mind, helped by the involvement of a not too helpful doctor, his entire life begins to unravel.

Believe me when I say this, if you are easily offended, this is genuinely not the film for you; it is sexist, racist, misogynistic and pretty much ticks every box to offend the largest amount of people possible. However, there is a large chunk of Filth that is hugely enjoyable, especially if something like South Park is right up your street. Yes, the humour is offensive but Filth is definitely a film that you will feel provides more than its fair share of entertainment.

On top of the above, McAvoy is barely recognisable as the not so nice Bruce Robertson, but it is moments which display his heart that make the performance what it is; Bruce helps a man having a heart attack on the street and becomes attached to his wife, mostly out of pure pity. It is arguably one of his finest career performances to date.

However, the film as a whole, much like it's lead character, is more than a little all over the place. Without a clear sense of direction, it seems to attempt to pack as many insulting set pieces into one film, while avoiding the actual plot. There could be a case made for the fact that Filth sets out to shock, without really paying much attention to what really matters.

Be prepared if you are easily offended, but otherwise, this is pretty enjoyable.