Dear Trudie,

As a child, I was conditioned to be suspicious of any white vans cruising slowly around my neighbourhood. As a film-geek, I am conditioned to be wary of any movie that has too many producers (especially when they give themselves cameos). In the case of Filth, there are a whopping 36 of you with titles ranging from 'executive' to 'associate' to 'co-'. You, however, received the classic yet understated 'producer' title, reflecting a more involved role on the film. Which means you can probably understand why films with more than five producers risk being mired in a 'too many cooks' scenario, delivering either a bland product or one brimming with too many ingredients that never seem to gel. Yet somehow, your film managed to avoid this outcome. With Filth, you and your 35 colleagues give us a film that is tasteless - in the best possible way.

As I'm sure you know, Irvine Welsh (executive producer here) is not for everyone. His first novel, Trainspotting, introduced us to a Scotland the tourism board definitely didn't want us to see. According to Filth, the place hasn't gotten better with time. Filled with greasy chavs, murderous teens, crooked cops and depravity on every corner, it's a place I wouldn't want to live, but it sure is entertaining to visit for a couple of hours.

Detective Bruce Robertson calls Edinburgh home. As soon as he's secured a promotion, he'll be reunited with his wife and daughter and once again be king of his own castle. There isn't any taboo Bruce won't break to achieve his goal, and he plays the people in his life - coworkers, associates, suspects and women - like chess pieces in an elaborate game where only he knows the rules. But the psychic cracks are beginning to show, and it's merely a matter of time before Bruce loses it all.

As the wife of Sting, I'm sure you've seen your share of rock stars years-deep into a lifelong bender. When we meet Bruce, he's already past the point of no return. The casting of James McAvoy is no accident, as he is also a producer, but his performance is undeniably singular. Bruce is a misanthrope we want to root for, mainly because McAvoy is able to give him a sliver of humanity where other actors might have gone full Bad Lieutenant. As he sinks down the rabbit-hole of iniquity, there's a hurt little boy standing at the edge staring down. Bruce is an amoral dirtbag, but he's not a cartoon.

There is a grotesque whimsy in Filth that calls to mind the delicious dark humour of American Psycho and Fear & Loathing in Las Vegas. As Bruce descends deeper into madness, he sees people with oversized farm animal heads and his doctor appears to him with exaggerated features made all the more frightening by the stark white light and funhouse reflections forced through a fish-eye lens. Even the sex is comically moribund. Bruce's eyes are sunken, his pallor is funereal despite his cocky swagger. Lit from high above we can see every crease and crevice, rendering his visage into that of the joker from a creepy deck of cards. How he manages to convince anyone that he's maintaining his grip while trying to solve a murder is maybe the grandest joke of all.

Perhaps it's because you have four kids, two step kids and Sting's massive ego to manage, but it seems you were able to navigate the labyrinthine plot strands and numerous producers deftly enough to make sure Filth _found a balance. You're no stranger to bringing the world loveable yet criminal protagonists. Your production company gave us _Snatch and Lock Stock and Two Smoking Barrels, which introduced cinemagoers to Guy Ritchie. That you then introduced Guy Ritchie to Madonna is an offense I'm still not sure I can forgive, but Filth has seriously made me consider it.