“Line of Duty” (BBC Sunday night) is a pretty good show. But I don’t quite understand the obsession.

Certainly well acted and well written and we now have just two episodes left to see “H” unmasked.

Drama requires a suspension of DisBelief. The acting and the writing are so good that we can overlook some holes in the plot. This is the fifth series and perhaps the most unbelievable aspect is that in a provincial police force (probably in the English East Midlands) at least five police officers can be killed in a very short time and the English Media has not descended on the area. Not to mention the police casualties from Series 1, 2, 3 and 4.

And it also seems strange that so many senior police officers don’t actually know each other. Havent they come thru the ranks, been on training courses or served together fr years?

Viewers as on Gogglebox and Twitter seem to say things like “I didn’t see that coming”. But actually they cant see anything coming because it is all in the writers hands. The storyline can go anywhere.

It may be set in the East Midlands but it is filmed in Belfast. Hooray for us. The police anti-corruption squad seem to operate out of Bedford House in Bedford Street, the police headquarters is in Belfast Central Library and police firearms units are running around Custom House Square and Tomb Street Mail Sorting Centre.

There are some nice in-jokes. Did anyone notice that Steve told someone at the other end of the phone that he was “in Tates Avenue” and yes that’s where the show was on location.

But as well as being filmed on the streets of Belfast, it now seems that Belfast is central to the drama and perhaps all thru this series and maybe other series you spotted this seemed likely.

So here is my theory.

Hastings (Adrian Dunbar) is ex-RUC and heads the anti-corruption unit. Freemasonry has been mentioned a lot. Is he one? Yet he seems to say “Mother of God!” a lot which is a bit Catholic and has an ex-wife called “Roisin”…..which is also a bit Catholic isn’t it?

Hastings and Roisin are heading for divorce, in part because he lost all their savings in a scam. Those who point to Hastings being “H”, the criminal mastermind have overlooked the fact that he has very little money and the cash in an envelope from another ex-RUC man who is apparently working on getting money back from the scammers is a Godsend. But really this ex-colleague looks a bit dodgy.

A major clue was dropped in Episode 3 when the unseen “H” mis-spelt “definitely” as “definately” …twice. And in Episode 4, Hastings also spells the word as “definitely”.

Is Hastings “H”? ….well perhaps Hastings knows that the real “H” mis-spells the word. Or maybe the real “H” knows that Hastings cant spell the word.

It turns out in Episode 4, newly murdered (I didn’t see THAT coming) , rogue undercover cop, John Corbett was born in Belfast as “McGuinness/Magennis/McGinnis” (we have not seen the name wriiten but trust me there might be a clue in that spelling) and his parents were killed during the Troubles and John was adopted in Liverpool where he developed a very good Scouse accent (nobody does it better than Stephen Graham) and possibly an animosity to Hastings as he has spent four episodes pointing the finger at Hastings.

So we have five connexions to Norn Iron….Roisin (beaten up by Corbett), Hastings, Corbett, the other ex-RUC man with a lot of cash…….and a voice captured on tape.

That’s a lot of Norn Iron connexions merely for it all to be a shoal of red herrings.

Hmmm….dodgy dealings in the RUC in the 1980s? I find that very hard to believe.

The writing can take the story in two directions at the whim of Jed Mercurio, the writer. He has Italian parents (Catholic?) . He is a former doctor in the British Air Force and there may be clues as to how he sees the world in his back catalogue of (usually) hospital dramas.

If I make the leap and think that “Line of Duty” secrets are Belfast-based, then scenes from Episodes 5 and 6 could easily be filmed in Gilnahirk or Andytown.

What kinda RUC man was Hastings? A good guy caught up in it all. Catholic? Special Branch? Rogue? A man who covered up or a man who blew whistles?

Will the RUC be the good guys? Or the bad guys? Collusion? Deep State? Or an untidy inconclusive ending which is just like real life.

The Achilles Heel of  “Line of Duty” is the way the narrative changes…even within episodes. The TV audience views it one episode at a time but presumably Adrian Dunbar, Martin Compson and Vicky McClure received all six scripts and know how this story ends …they aren’t just doing it on a week-to-week basis. So they are good actors and have the skill sets to achieve consistency in their characters.

And hopefully Adrian Dunbar has a BAFTA on his mantelpiece before the end of 2019.