But Righteous Kill is still an absorbing couple of hours in the murky world which defies and ultimately corrupts the New York Police Department.

A succession of "low-lifes", as everyone one colourfully calls them, are found brutally murdered, shot at point blank range, the killer's calling card each time a rather-sanctimonious little poem which suggests they got what they deserved.

Pimps, dealers and even a child-abusing priest are among the victims. The one thing they share is that they have slipped through the police's fingers one way or another.

All of which raises the question: is this the work of a hacked-off policeman, frustrated beyond all endurance by a criminal justice systems which lets too many villains get away with their crimes?

It's the question detectives Turk (Robert De Niro) and Rooster (Al Pacino) have got to answer. Except that it's a question the film seems to answer right at the outset.

The movie kicks off with one of them apparently confessing – a sure sign that absolutely none of what follows is going to be remotely what it seems.

The result is fairly gripping stuff, everyone compromised in a grim world in which there seems little left that's good for anyone to cling on to.

De Niro and Pacino are mostly terrific together as the hard-bitten old-timers, delivering all their familiar tics and mannerisms, but always keeping up the tension as the bodies pile up around them.

Phil Hewitt.