James McAvoy on his 'nastiest' role
2 October 2013 Last updated at 16:42 BST
Actor James McAvoy talks about his role in the new film Filth, which he says is his "nastiest" role yet.
The film charts the downfall of McAvoy's character - Bruce Robertson - within the police force, and his interference in the private lives of his colleagues.
The film Filth comes 17 years after Irvine's first novel, Trainspotting, was made into a cult film.