Nick Cassidy (Sam Worthington) is an ex-New York City cop sent to jail for stealing a $40 million diamond. Of course, he didn’t steal the diamond and was convicted because corrupt policemen gave false evidence. The film is about Nick’s plan to clear his name and get David Englander (Ed Harris), the real bad guy, to pay for his crime.

Nick gets a respite from prison to attend his father’s funeral. He uses the occasion to escape, flees to the hotel and climbs onto the ledge announcing his intention to commit suicide. As the title suggests, Cassidy spends most of the film on the ledge outside a window on the 21st floor of the Roosevelt Hotel in Manhattan. (Does the hotel really still have windows that open?)

Of course, the suicide is a ruse to distract law enforcement and buy time for his brother Joey (Jamie Bell) to find the diamond Nick is convinced is hidden in Englander’s office.

Police hostage negotiator Lydia Mercer (Elizabeth Banks) comes to the scene to talk Nick down but, as the movie goes on, she begins to take his side against his former partner, Mike Ackerman (Anthony Mackie).

There is a degree of tension and suspense in Man On A Ledge. That suspense is heightened if you compare it to the boring Mark Wahlberg movie Contraband.

The movie was written by Pablo F. Fenjves, whose claim to fame — or, infamy — is that he lived next door to Nicole Brown Simpson and it was he who heard her dog barking the night she an Ron Goldman were murdered. He later served as ghostwriter for the execrable OJ Simpson book, If I Did It. It was directed by Asger Leth.

Sam Worthington, who most of us know most from Avatar, is a worthy hero. We want his mission to succeed and the rest of the cast — including an emaciated, glowering Ed Harris — is fine. One bright spot is provided by Kyra Sedgewick as an obnoxious TV reporter who directs her station’s helicopter to fly into Nick’s face as he’s on the ledge. She’s every newsperson’s nightmare of how the profession may be portrayed.

It’s the film itself that lacks a sharp edge. It simply could have been much better.