There's no doubting that the Brits do this kind of gritty police drama better than anyone else. Great, engaging and flawed central character, with lots of real human traits - that make him both likeable and worrying. Temptation, seduction, power, betrayal and guilt in bucket loads, dosed with equal amounts of murder and mayhem. But... all done at suitable drawn out and nail biting pace. Tension is really strung out and works well to keep you on your seat each and advance the plot. A little too clever in a few places, which breaks your suspension of disbelief, but otherwise 'golden'.