I watched Downton Abbey the other night, for the first time. Before that, my only contact with it had been sitting next to Hugh Bonneville in the Business Class lounge at Los Angeles airport, and that was only because Air NZ lost my luggage for nine days on the way out and had to give me enough points for an upgrade. That’s a tale for another day.

Anyway, Downton Abbey, the finale. Oh dear. I wasn’t sorry I hadn’t seen the rest of it. Being charitable, perhaps the dire script was the inevitable outcome of the scriptwriter’s mission impossible – tying up far too many storylines in one episode, as well as fitting in the obligatory set pieces complete with valedictory one-liners and extravagantly costumed extras by the bus load. Poor bugger. I hope he’s lying in a darkened room, or on a beach somewhere far away from a television.

The whole affair was an object lesson in what happens when dialogue carries too much plot. ‘Oh hello, Fanny/Cedric/ whoever, I haven’t seen you since Lady X ran off with the butcher and then we all went hunting and Albert broke his leg. How are you?’ ‘Very well, thanks, and so much better since I recovered from that bout of flu in Episode 6 which nearly killed me and made me realise that life Is short and I had to divorce Dierdre before my fiftieth birthday.’ Fortunately, as I watched this farago I had a DA veteran in the room to answer my queries, although she was annoyed by my irreverent approach. ‘But it used to be good,’ she maintained stoutly. ‘This is just the end.’ Oh it was, it was.

Imagine my surprise when serious Tweets the following day praised everything I’d found risible. ‘Wasn’t it wonderful how they managed to tie up all the story lines so neatly,’ the DA fans purred, as if this was a good thing. I could only surmise that tying up every loose end was a genre protocol which had been slavishly followed, at the cost of any dramatic authenticity. Characters and plot were all left hopelessly two-dimensional, however well they may have been portrayed in the past. I suspect the actors knew they had became caricatures of themselves: maybe they wept quietly into the post-production champagne.

Many years ago, in the very first course I did on ‘How to write a novel’ (Arvon, 2007, at The Hurst) Louise Doughty spent a couple of hours on dialogue, which I’ve never forgotten. First she gave us a transcript of actual conversation, including every non-sequitur, hesitation and repetition – which was almost impossible to read. Then we had another example of the kind I’ve alluded to above: ‘Oh hello George, how good to meet you on a lovely day with the bluebells unfurling into spring sunshine etc’ which was as unnaturally ghastly as many of the lines in the DA finale.

The desired path is somewhere between the two, of course, and hard to navigate. Dialogue needs to be read aloud by the writer, because spoken conversation differs in so many respects from the written form: very few complex sentences, some hesitation and repetition, and many contextual details taken for granted, which the writer has to supply by other means. The writer can indicate the tone of voice by adverbs, or variations on ‘said’, but most of them sound clunky. The reader has to be helped to keep track of who’s speaking, without the luxury of seeing who is doing so.

As part of the initial ‘character studies’ that I develop when someone new is introduced, I try to hear how they will talk. What kinds of verbs and metaphors might the person use? Do they have any characteristic phrases, interesting in themselves and also indicative of a state of mind? Do they interrupt others during conversation or listen carefully and respond? Do they think before they speak, or put a foot in it occasionally, and how will this affect those around them? I’m sure every good scriptwriter will do the same, until and unless the demands of the plot get in the way, as they did at Downton Abbey over Christmas.