The first episode is amazingly good.
Pacing is excellent, great actors, interesting characters.
The flaws?
1) Killing Julia off.
She was such a crucial character that the episodes after her demise were lacking.
2) The final episode.
As other reviewers have said, it was full of plot holes. I'd agree with many of other reviewers statements regarding a talented bomb-maker blowing herself up, and the sudden urge to confess by several characters just didn't ring true.
Still, ignoring those flaws, I really enjoyed this series and hope they make a second series.
Oh and I nearly forgot to mention, Keeley Hawes is HOT!
Oh and I nearly forgot to mention, Keeley Hawes is HOT!