Black Mass, film review: Johnny Depp gives a chilling performance

(15)​ Scott Cooper, 123 mins. Starring: Johnny Depp, Dakota Johnson, Kevin Bacon, Benedict Cumberbatch, Juno Temple

Chilling: Johnny Depp as mob boss James ‘Whitey’ Bulger in ‘Black Mass’

Johnny Depp gives an utterly chilling performance as the notorious James "Whitey" Bulger in the Boston-set crime drama Black Mass. He has played gangsters and petty criminals before but never one as cold-hearted as Bulger. This is a man who will throttle a young prostitute to death before going off to dinner and who will pummel an informer to a bloody pulp – even though he is sharing secrets with the FBI. Here, Depp looks nothing like the wistful charmer we know from Tim Burton movies. Bulger is balding and has his hair slicked back. His teeth are bad. His personality is on the vicious side of psychotic.

The effectiveness of Depp's performance turns out to be part of the problem in what is an uneven film – one that is very hard to like. The film tells the jaw-dropping story of how Bulger, a low-life Irish-American hoodlum from south Boston, became the dominant figure in the city's underworld, thanks largely to the FBI's connivance. FBI agent John Connolly (Joel Edgerton), who grew up alongside Bulger and held him in awe, persuaded him to become an informer. Bulger helped the Feds to bust the Italian mafia – and then took over from them.

The director, Scott Cooper, does an effective job of portraying the Boston underworld. This is a film that takes blue-collar 1970s grittiness to extremes. Cooper has assembled some tremendous character actors to play Bulger's henchmen in the so-called Winter Hill Gang. There is W Earl Brown as the chubby, none-too-hygienic Johnny Martorano, the gang's main executioner, who commits murder in an eerily calm, matter-of-fact way; Rory Cochrane as his trusted pal, Stephen "The Rifleman" Flemmi; and Jesse Plemons as his hard-brawling young associate Kevin Weeks.

Dakota Johnson (in a role a long way from 50 Shades Of Grey) is affecting as Bulger's long-suffering wife, while Juno Temple registers very strongly in a tiny cameo as a hooker. There isn't much spark to the relationship between Depp and his vain and increasingly combustible FBI handler Connolly. True to life – and to genre conventions – Connolly begins to behave more and more like the gangsters he is ostensibly trying to bring down. In a full-blooded and sometimes blustering performance, Edgerton shows us the mix of hero worship, tribal loyalty and career ambition that makes him so deferential to Bulger, but there is no sense that the two men are friends. As a buddy movie, the film is therefore a non-starter. It also seems perverse for Cooper to cast an actor as accomplished as Benedict Cumberbatch as Bulger's brother, the prominent Boston politician William Bulger, and then give him so little to do.

Black Mass is a triumph of sorts for Depp. It shows him tapping into a malevolence and cruelty that many fans would never have guessed was in him. As a gangster movie, though, it is a frustrating and strangely dour affair.