I watched the series on Netflix a couple years ago and it was one of the best police series I have seen, notwithstanding the fact that it is British and centers on the work of the Metropolitan Police. It's one of a handful, which include "The Wire" (my favorite), and Bosch that get the feel right...both from the point of view of the street work and cases...and dealing with "the job".
Here's a link from YouTube to hopefully get you on your way. I really don't think you'll be disappointed. It's quite good.