Excellent, suspenseful thriller. Adapted from Robert Harris' Ghost.
Doesn't do justice to the excellent book, which is utterly and chillingly believable, simply because the (changed) conclusion doesn't really hold water, and the cuts to the details of the plot (made to compress the story) have left some of the scenes looking unlikely.
However, all that's only a problem after the film's over. While you're watching it, it's really rather good.