Des episode 3, review: David Tennant remained skin-crawling, but finale left too many unanswered questions

There’s always been something frustrating about British crime dramas. Whether real or imagined, there’s a nagging sense that a formula must be adhered to – a killer will be apprehended early, there will be a battle of wits between them and a police officer, and a trial shall commence. A verdict equals an ending, and a postscript ties up any loose ends. Des (ITV), disappointingly, followed such a routine to the letter.

Tonight’s climactic episode of the Dennis Nilsen story was still compelling and brilliantly acted, but it felt a bit too standard in its goals. It was something made more frustrating by the ambiguity of those aforementioned postscripts.

Daniel Mays and Jason Watkins have been marvellous as flustered copper Peter Jay and Nilsen biographer Brian Masters, respectively, with both actors lending their characters a sense of personal uncertainty when it comes to their own actions. But neither character had much of an on-screen resolution here.

We learnt that Jay left the police force two years after Nilsen’s conviction, but what led up to that was open to interpretation. And while Masters appeared genuinely terrified by what seemed to be his last interaction with Nilsen, his own postscript revealed that he continued visiting the imprisoned killer for a decade. What of those years? What kept drawing him back? We may have seen Jay struggle against the soulless bureaucracy of the police, but not the thing that must have finally pushed him over the edge.

If Des’s second episode felt so assured about its various storylines, uninterested in making this series a straight-forward recounting of the Dennis Nilsen story, the third instalment seemed to backtrack.

Crime dramas don’t need to end with a trial and a conviction, with sometimes the most challenging and complex ideas surfacing when everything seems to have been wrapped up. It felt like Des missed the memo.

Still, it’s undeniable that we’ve just witnessed one of TV’s greatest performances thanks to David Tennant. There will be a point in a few years when every notable actor will have had at least one serial killer role to their name, but even then Tennant will most likely stick out. Much of his actual dialogue wasn’t particularly frightening, the grotesque barbarism of his crimes exclusively verbalised by others, but it remained a skin-crawling bit of acting.

Its enrapturing power may have been in those strange sounds Tennant made whenever Nilsen finished a sentence, a kind of gesturing verbal tic said so often that “Do you know what I mean?” is now just a phlegmy gurgle. Regardless of how he did it, he’s been incredibly uncomfortable to watch – the on-screen equivalent of encountering a stranger in a supermarket queue you just know is a wrong ‘un.

Des’s send-off may have been underwhelming, but Tennant’s chilling performance made the journey getting there worth it.