This is a mystifyingly horny film. It's not mystifying why it's horny—I'm the world's biggest defender of the idea that vampires ought to be horny!—but in the way it goes about it. There is of course the almost softcore blatancy with which the camera constantly caresses Mathilda May's massive tits, but that really just serves to set the stage for the pervasive sexuality of the whole thing. The one-two punch of "I can read her mind and she's a masochist" / "well I'm a natural voyeur", in a scene notionally about tracking a monster that's actively killing people, stands out in my mind, as does the sweaty desperation of the prime minister. But really I think there's barely a moment here that's not sexual in one way or another.
The film draws an immediate and firm connection between sex and the theft of lifeforce (General Ripper would be right at home). Even the first time we see it in a human-to-human context, the emaciated guard grasps at the air as though to initiate an embrace and the doctor who becomes his victim approaches out of tenderness. We can then read the fall of London as a sort of self-destructive orgy, a modern Sodom. Our two heroes are defined as heroic by their abstinence: Caine just likes to watch and so always has an objective position and knows what to do, and Carlsen has the astounding ability to choose not to have sex with a beautiful woman—or, at the movie's climax, to stop having sex just before it reaches the point of no return.
This is an approach to sex that sits at the particular crossroads between heteromasculinity and Christianity. It conceptualizes the ultimate horniness as an overpowering urge to overpower, and because overpowering others is wrong it conceptualizes everything about sexualith as immoral. But this totalizing view is in turn undermined by the film itself clearly existing to titillate the (presumedly heteromasculine—note that the only reference to queerness in the film is from the perspective of men wanting to watch lesbian sex) viewer. The film gives itself a gentle cloak of irony, playfully casting the viewer in the role of Caine the voyeur and the reframing the film's Christian bent as more of an erotic roleplay than a genuine expression of values.
It's a fascinating artifact, and one that—despite the intense heteromasculinity that no amount of irony can purge—I'm inclined to appreciate. Because at the end of the day, I think vampire films should be about sex, and I'll be damned if this is not a vampire movie that is well and thoroughly about sex.