An absolute tour de force from James McAvoy. Easily his greatest screen performance, and considering he's Mr. Reliable in pretty much anything, that's some measure of just how sublime he is here.
He's more than ably supported by a saints row of British talent, not to mention Jon S. Baird's wonderful direction, channeling the bizarre, twisted Welsh novel through it's murky yet vibrant colour palette, wicked interludes and off-kilter narrative that feels entirely like the breathless, coked-up, hangover-enduring frenzy of it's frontman.
Trainspotting will always be held up in comparison, but for my money, this is the best Welsh adaptation, as it descends into a state of paranoid rebelliousness that Renton and Co. could only flirt with. Boyle reached the masses with his tale of heroin outlaws because despite the grime and grit, he showcased all his mainstream skill above the horrors.
Filth never reaches for such heights, it just wallows gleefully in it's own dark-hearted misery and well... filth.