Based on a book of the same name (I haven't read,) it takes place in an alternate universe Britain in the 90s. The acting was very good, and the story was somewhat slow; but interesting throughout. It's a meditative thought experiment set in a slightly science fiction setting.
I enjoyed it; though, I found the premise implausible. It's one of those that I can't expound on without ruining the experience.
I would recommend it if you are into more "artsy" sci-fi. It's in the same vein as Gattaca; but not as spectacular.