It proved surprisingly easy to pick up this series from here and the mixture of quirky/odd characters and plausible spy shenanigans proved to be a very entertaining (and frequently very funny) one. The top-flight cast was superbly led by Gary Oldman as the anti-hero. He was surrounded by a range of masterly performers and performances which did not fall into the trap of being too weirdly idiosyncratic.
Well worth catching up from Season 1 I think.