It is an unedifying film, slickly directed and photographed, but lacking conviction and much inferior to the police procedurals you can see any night on television.

All three men give searing performances and young cinematographer Robert Hardy dwells with palpable relief on their expressive features.

Who knows, we might be looking at the evolution of the guilty-pleasure movie - padded out with top-drawer talent to spare audience blushes.

Smart, sharp, shocking, and at times bloody (and bloodily) hilarious, Blitz's witty script and pacy action elevates its simple premise into a brilliantly gritty tale of moral ambiguity.