Law & Order UK is a great show
I didn't like it. Firstly, it's got him from Coronation Street in. I can't take anything seriously with him in.
Secondly, I think there's quite a difference between British and American crime programmes and setting an american show in the UK doesn't really work very well. It also feels like it's america saying "your cop shows are crap, try one of ours".
If you want decent British crime telly try Waking the Dead, Silent Witness or Prime Suspect.
If you're after something more lighthearted there's Midsomes Murders and Jonathan Creek.
Then there's the classic like Poirot or a modern interpretation of a classic like the recent sherlock miniseries.