Just as the clinching piece of evidence arrives in the final episode of One of Us, detectives Juliet and Andrew seem to lose interest in the whole thing.

Though I wouldn’t go so far as to say I felt the same, it was certainly a less nerve-wracking sprint to the finishing line than I was expecting.

As predicted after last week’s talk of blood tests, Grace turns out not to have been Bill’s daughter.  Mind you, I was a little wide of the mark with my guess that the father was oddly-accented blue-eyed farmhand Alastair; the truth, and arguably the secret that has driven the whole story, is that Grace’s real father was the late Peter Elliott.

If the show was channelling the spirit of Take the High Road a couple of weeks back, this week turns out to be a riff on the opening plotline of Sons & Daughters because of course this secret means that not only were Adam and Grace husband and wife, they were also brother and sister.

As the episode progresses the evidence points more and more at Bill Douglas being the killer, so it’s a bit disappointing when it eventually turns out that he really is.  Rightly or wrongly, I was expecting some final twist to turn everything we thought we knew on its head – and in the absence of that, what we get is a convenient confession out in the farmyard before Bill decides not to kill himself after all.

I’m not sure I’m totally convinced even now.  The motive seems to have been an almost-religious outrage at the sin of a brother and sister being ‘together’.  Yet this holy attitude doesn’t sit all that well with the number of commandments Bill’s broken on the way (especially the killing and the lying).

As for the police, with Adam’s call history and some crucial DNA evidence all in place the rather low key arrest is left to the local cops, leaving Juliet free to get on with her own subplot of underhand drug-dealing, and to all intents and purposes she goes on the run, headed for India and hopefully an operation on her daughter’s brain tumour.  Fellow detective Andrew has worked out what’s been going on, but lets her go – which would be a little less uncomfortable if the drugs she’d sold hadn’t already killed at least one innocent victim.

So… it’s been watchable, but it’s hard to feel that One of Us has been ultimately very satisfying.  With its evident desire to tell us something about parents and children, about how far we will go for the ones we love, about right and wrong, and justice, and morality, it could have made a superb novel.

As it is, One of Us made for an entertaining series, but has not really set the world alight.

Aired at 9pm on Tuesday 13 September 2016 on BBC One.

Buy One of Us on DVD on Amazon here.

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