I’m tempted to say Slow Horses, but there’s just something about it that I think keeps it “merely” excellent instead of an all time great.

I kind of want to check out some of the books because I suspect it’s the underlying source material that keeps it from being transcendent, and the cast and screenwriters are actually elevating the material, at least a little, and they’re making it the rare “adaptation is better than than the book” situation. The fact that the series has evolved to be basically a novel or novella every year makes me thinks later entries may be pretty formulaic.