Just watched this over the weekend. Good show.
It's about a Manchester cop who gets hit by a car, and wakes up to find himself in 1973. He has a detective's job there too (apparently he just transferred there). Basically we have a cop show about the guy who doesn't fit in, as he tries to cope with the sexist, violent, corrupt cops he has to work with there. There's also the question of what is going on, told via moments when he seems to hear things going on around him (if he's in a coma or something).
There's great acting all round, good scripts, and generally a good cop-show feel. The cases aren't always very convincing - they seem tailored to be more about our hero's issues than anything else.