First off, despite the vampires and blood-letting, this is not a horror movie. This is a Science Fiction film set in a parallel world where, 300 years ago, vampires were created by an early form of genetic engineering. They are born, infrequently, from human women and are all male. Rather than act as predators, they have set themselves up as protectors of humanity and have organised themselves into the highly respected Brotherhood where they function as a cross between priest and scientist, receiving voluntary donations of blood. Technologically this world is very different from ours with a technological level that echoes, sort of, the 1950s but crossed with Victorian steampunk -steam-engined cars for example. A genuinely different world is convincingly created despite a low budget and is worth seeing for this alone.
The villain is a vampire whose illegal, but unofficially sanctioned by his superiors, experiments have changed him and he's become a predator of humans. However, his real motives are far darker than mere bloodlust. It's unfortunate that he resembles Bob Geldof on a really bad day. Dougray Scott effectively plays the taciturn vampire hero who has to track the villain down. Saffron Burrows is even better as the efficient but emotionally-damaged police detective nominally in charge of the operation, which is also a coverup, and who becomes Scott's unrequited love interest. Unfortunately that also makes her a prime target for the villain. And that is just the setup.
This is an intelligent and skillfully made film which deserves to be better known than it is. It doesn't, however, work quite as well as it should, possibly because of its unrelenting grimness, not helped by being mostly set in a slum within an industrially polluted city. However, if you want to see a Science Fiction movie which attempts something different, I strongly urge you to give this a try as you may find it surprisingly rewarding.