Actor Michael Caine poses for a picture in New York April 6, 2009. REUTERS/Shannon Stapleton

Commercials director Daniel Barber calls his feature debut, Harry Brown, an urban Western, which suggests the film's allure and its problem.

In the film, a pensioner goes on a wild vigilante-killing spree after an elderly friend is killed by a bunch of toughs in a rough, impoverished London neighborhood.

It's Destry Rides Again, only with an old codger rather than a mild-mannered youngster who surprises bad guys and cleans up a corrupt and lawless inner-city estate (a project in American terminology).

Since Michael Caine is that old codger, Harry Brown has box office potential. Lionsgate distributes in the U.K., but HanWay Films should make more than a few international sales riding on his name.

The attraction here is witnessing an elderly man turn the tables on a bunch of sneering, drug-snorting thugs. Following the deaths of his wife (by natural causes) and best mate (at the hands of the punks), old Harry has little reason to worry about either his own life or capture by the police.

The police are caricatured anyway, as dogs chasing their tails -- with the exception of the one caring detective, played by the always-reliable Emily Mortimer -- while the punks are irredeemably vicious. The movie, written by Gary Young, wants to think it's making a comment on rising violence in the U.K. but since the source of that violence -- the lives and backgrounds of gang members -- goes unexamined, the film is really designed as a shooting gallery. It's high noon all the time.

Indeed, the only character examined at all is Harry himself. He is an ex-Marine who buried memories of war and killing when he married his beloved wife. But with her gone, he can go into psycho killer mode.

It's a superficial examination, merely glancing into the details of a lonely existence in genteel poverty. Then the transition from aging chess player to urban commando is absurdly abrupt.

The carnage is profound with evidence everywhere that old Harry has his hands in it. Perhaps the film is implying London police don't mind old men cleaning out pond scum for them. Certainly Mortimer's character figures things out, but she will owe her life to Harry so best to keep these things under one's hat.

The film looks scruffy and certainly makes its environment look dangerous. Martin Ruhe's dynamic camera, especially in hand-held scenes, brings a rush of adrenaline into this urban wasteland. Kave Quinn's design emphasizes mind-numbing drabness whether it be domiciles of pensioners or the graffiti-marred hangouts and hideouts of the toughs. No wonder everyone including Harry wants to set fire to things.

So it all comes down to Caine, who makes the whole thing workable though not believable. Despite his efforts, the Western format fits awkwardly into an urban hell. For Destry did have the law on his side. He found a unique way to bring public opinion and legal tricks to bear on bad guys. Dirty Harry Brown just wants to outgun them.