A very minimalistic, neo-classical soundtrack which is nothing but brooding and brooding, untill the sudden swell of the horns which die away as fast as they came. It's made of course for the suspense of the movie, but it holds up really well on it's own. And there are a few OST that can say that.
Rob Dougan is hurt, and he's mad, and he's got the tools to translate that into jazzy filmscore music. A raw voice with catchy hooks, makes for a formidable record. On multiple spins it becomes clear that all the classical instrumentation is 'fake', but in the trip-hop roots that shouldn't bother.