Thriller/Action/Romance. Mark Wahlberg, Russell Crowe, Catherine Zeta-Jones, Jeffrey Wright, Barry Pepper, Natalie Martinez, Kyle Chandler, Alona Tal. Director: Allen Hughes.

We don’t need serpentine thrillers such as Broken City to remind us that politics is a grubby business.

As recent headlines attest, elected authority figures who we trust to shape and reform our laws can occasionally ride roughshod over those same rules and regulations.

Allen Hughes’s film argues that to affect lasting change in the corridors of power, you have to be prepared to get your hands bloody. Or pay someone else to get their money-grabbing mitts filthy on your behalf.

The anti-hero in Broken City is New York cop Billy Taggart (Mark Wahlberg), who takes down an unarmed suspect and faces a prison sentence for his apparent lapse in judgment.

It looks like an open and shut case until popular Mayor Nicholas Hostetler (Russell Crowe) steps in with a deal, making clear to Billy that he expects a favour in return. Seven years later, Billy is a low-rent private detective.

He owes 42,000 dollars – the situation is dire, even with a brilliant assistant (Alona Tal) chasing up outstanding bills.

Out of the blue, Hostetler calls in his marker: he asks Billy to gather evidence to prove that his wife Cathleen (Catherine Zeta-Jones) has been unfaithful. Hostetler is embroiled in a bitter election battle with charismatic rival Jack Valliant (Barry Pepper), and doesn’t want a marital scandal to blight his chances.

Broken City marshals an impressive cast and Brian Tucker’s script sustains dramatic tension for the opening hour by teasing us with the characters’ ulterior motives.

But Tucker’s script becomes increasingly preposterous and is peppered with surreal one-liners that masquerade as gritty street talk.