I don't know why the British have a fascination with police programmes on television. As a child, I can recall watching "Z-cars", which was followed by "Softly softly". There was a tendency towards American shows during the 70s ("Starsky and Hutch" was required viewing), but the trend reverted to British shows during the 80s and 90s ('Morse', 'A touch of Frost').
At the moment, I am watching three different police programmes on television. 'Line of duty' - to which I have referred in the past - is now in its fourth season and is being shown here about one month after being shown in Britain, which is remarkable. This programme differs from others in that it shows policemen investigating policemen, as opposed to policemen investigating crimes. This is an excellent series, and one never knows what is going to happen. Apparently the show is scheduled for another two series.
Second up is 'Unforgotten', which is in its second series. This shows a unit which deals with cold crimes - murders committed thirty plus years ago. This is much more a drama series than a police procedural and as such is very well written. But looking beyond the story itself, one sees several items which deserve explanation. Such a unit in real life would normally be where unwanted or burned out officers are placed; the officers in this unit are young and good at their job (the researchers are exceedingly good).
The deputy chief has even been promoted from Detective Sergeant to Detective Inspector between the first and second seasons, but no explanation - or celebration - was mentioned. The home life of the deputy chief is also unexplained: he has two teenage daughters but no wife. It's not clear whether he is a widower or abandoned by his wife; if the latter, then it seems strange that a very busy detective would win custody - unless, of course, we only see his daughters when they are with him. But this doesn't seem to be the case. A good rule of drama is "don't add unnecessary complications": whilst these scenes are supposed to make the character more interesting, they also throw up unanswerable questions.
The third programme, which has just started being shown again, is the third series of my old friend, DCI Banks. I have carped enough about this programme in the past, but I won't be returning to any of my old criticisms. The story in the opening episodes is based on a one line description of one of the better earlier Banks books, but otherwise is a completely new invention. Thus I don't know where the story is going, and instead of complaining about how the original has been adulterated, I can watch the show with new eyes. My earlier complaint about the apparent continual stroppiness of the titular character has been answered: he is now much more calm, but the stroppiness has been transferred onto his subordinates, specifically DI Morton (a character invented for the screen presumably because the actress playing DS Annie Cabbot went on maternity leave) and DS Cabbot. I doubt very much whether police officers could continue to behave the way that DI Morton does without being reprimanded. As opposed to the other programmes mentioned here - and as opposed to the books - I can't see any special characteristic which defines this programme and differentiates it from others. This lack of differentiation lowers its value.