The concept is definitely a good one, one of the darkest 'what if's' you can imagine, what would Britain have looked like if the Nazis had won the war?
As always the BBC gets the visuals spot on, the whole thing looks fantastic and slick from start to finish, the costumes, sets, effects are all amazing, it looks incredibly high budget. The story is very engaging, the first episode is a bit of a drag, but get past that and it opens up very well. It's definitely better then The Man in The High Castle, so much more realistic, you watch this and realise it could have happened, this is what life could have been like.
The sound at times was a little bit poor, with a little bit of mumbling, not a great deal, definitely nothing like Jamaica Inn. Accents, however, spot on, I'm glad they didn't use non authentic dialects.
If you're a fan of film noir, this will suit you, I hope very much that we get a second series. 8/10