As Downton Abbey and The Newsreader conclude, what is the best way to end a beloved TV series?

I had been waiting eagerly for it to air in the UK and rationed my viewing like a desert water supply, conscious that when its final credits rolled, that would be the last I’d see of it. The good news is that the series goes out in style with nothing to disappoint.

I recently discussed the business of how to end a beloved long-running series with Julian Fellowes, who has delivered what he says will be the final chapter of his great opus, Downton Abbey.

Of the difference between writing earlier chapters of his juggernaut period drama and deliberately closing the book, Fellowes explained: “Up to the last, you’re always trying to attract a new audience, but by the last episode, you’re trying to thank them. They’ve stayed with you, and you’re not trying for new people. Either they enjoyed the show or they didn’t.” Is it the Greatest Hits album? “Yes.”

His words are a useful yardstick by which to judge recent TV endings that have left audiences variously satisfied, cross or just scratching their heads (yes, Lost, I see you). The consensus on the much-hyped finale of Game of Thrones – aka “the world’s biggest TV show” – was that its producers threw too much at the screen, created some stunt romantic coupling and finally plonked the wrong person on the actual throne. But who would have been better? After eight labyrinthine series, it was hard to say.

By contrast, many who watched the denouement of Line of Duty were furious that writer Jed Mercurio hadn’t done enough. I’m in a minority of people who applauded his nuanced pay-off of incompetence rather than comic-book evil allowing corruption to flourish. But such is the clamour to have a bigger ending, it looks like Mercurio will have to dust off his writing pad and give viewers the bang they demand.

At least he made an effort, which is more than can be said for the writers of And Just like That… Following an abrupt announcement last month that the Sex and the City sequel would be finishing for good after its third season, the weak storyline (along with some scenes that I will struggle to flush from my memory) succeeded in ruining the legacy of not one but two much-loved shows.

Let me swiftly turn and doff my cap instead to a comedy whose ending not only matched but transcended all that came before. I refer, of course, to the magnificent Blackadder Goes Forth, whose poppies in a foreign field offered a poignancy made all the sweeter after four series of belly laughs.

Of the three great dramas (yes, it’s subjective!) of US television’s so-called golden age, two – Mad Men and The West Wing – ended with panache, delivering subtle and satisfying nods to all that went before. The third – The Sopranos – remains much more controversial. Its ambiguous final scene has long divided fans, but begs the question: what is it we want from our fictional endings?

The more we love a show, the less we want it to end, but if it must, can we at least leave characters in a good place? Maybe, but that’s not life. The Sopranos opted for something braver and more real – and, as it had always done, left us guessing. Or, as another artist, Paul Gardner, would have it: “A painting is never finished, it simply stops in interesting places.”

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