Searingly powerful, dark, difficult and sad, Monster’s Ball qualifies without doubt as one of the best and most assured movies of this year, or last. Despite slight melodramatic excesses, this Southern Gothic meditation on capital punishment, poverty, parental violence, sex and bereavement packs a pretty remarkable emotional punch, in the process painting US society in a deeply unflattering light.

Billy Bob Thornton excels, as ever, playing Hank, a vicious racist whoring Southern executioner who inherited the grisly job from his even nastier father Buck (given to observations such as: ‘Hank, I got much more pussy after your mother killed herself’). Hank’s long-suffering wife has gone the same way, while his tortured son (Heath Ledger) works with him on the execution line, to the son’s extreme dislike.

In the grim penitentiary, black inmate Laurence Musgrave (Puff Daddy) awaits execution, with his wife (Halle Berry) and young son (Coronji Calhoun) paying their last visits. A convenient, but compelling, confluence of circumstances then conspire to draw the lives of all the protagonists together – along the way, there’s the most disturbing death-penalty sequence ever witnessed on film, gunshot suicides, hardcore inter-racial fucking, hit-and-run fatalities, and the endless hacking wheeze of old Buck’s emphysema.

While Berry’s Oscar got the headlines, and Thornton is typically supreme, Puff Daddy is arguably the real revelation here: one of the least talented recording artists of all time, but a born actor on this evidence. Even the previously undistinguished Heath Ledger doesn’t put a foot wrong.

It might be argued that some of the film’s key coincidences are too neat to be swallowed whole, that Berry’s emoting sometimes borders hysteria, that few of the players are people you’d want around the place... but by any standards, Monster’s Ball is highly impressive stuff.