Welsh-born Christian Bale's riveting performance as a Gulf War veteran looking for work in LA is the chief reason to see this tough and pessimistic film, written and directed by David Ayer.

A subsidiary one is Ayer's frightening sense of what can become of such a soldier who wakes up screaming in the night, has burnt through his savings waiting for a job in the LA Police Department and seems to be going nowhere fast.

These are pretty mean streets he drives through in his battered car, usually accompanied by his unemployed and feckless best friend (Freddy Rodriguez).

Drink and drugs and general mayhem seem the only way to relieve his disappointment at not getting a job and not being able to marry his devoted Mexican girlfriend (Tammy Trull), whom he wants to bring back to the States.

He is on the edge of despair when offered a post in Homeland Security, which means travelling into druginfested Colombia where his tough military background will help him "terminate" the dealers.

It is employment that appeals to the worst side of his nature and, almost inevitably, his incipient psychosis manifests itself.

Ayer's portrait of the group of young men who roam LA cheating on their girlfriends and living high on little or no prospects carries reminders of Scorsese's Taxi Driver, and Bale's performance is almost as notable as Robert De Niro's in that film. You know he's on the edge of the precipice, unable either to deal with his past or to allow himself.to walk away from it.

Grittily made and well written, it goes into overdrive at the end and becomes more than a little melodramatic. But it forces you to ask the question: how many soldiers like this mentally wounded man are at present serving in Iraq?