Luther, Series Finale, BBC One

What a strange, shape-shifting thing Luther is. Storylines ebb and flow around Idris Elba's dauntingly huge central character like flotsam and debris borne along on a heaving swell, but the man himself wades imperiously through it all like the Colossus in an old Jason and the Argonauts movie. Gross professional misconduct, subterfuge and blatantly aiding and abetting criminal behaviour are all part of Luther's daily routine.

The show's disorientating aura gets an additional boost from the way seemingly crucial characters just go missing. Paul McGann's Mark North, erstwhile lover of Luther's now deceased wife, looked like he was being set up for something pivotal in the first couple of episodes of this second series, then vanished without leaving so much as a tweet or a phone message. Likewise, Ruth Wilson's Alice Morgan, a kind of pouty and redheaded Hannibal Lecter, received some of Luther's extra-special care before being brusquely swept offstage, though she did receive a belated mention in dispatches at the end of last night's final episode.

But as long as Elba is at the centre of the action, generating his own idiosyncratic centrifugal force like a vast thespian turbine, there's no need to worry. Despite his eye-catching role in The Wire and a burgeoning movie career, Elba is an East Ham boy through and through, even if he is an Arsenal supporter. Series creator Neil Cross has made a point of framing Luther, and indeed Luther, in vividly specific London locations from Smithfield to various points east across the City, and the show has maintained a sense of geographical integrity by refraining from cutting in make-weight extraneous shots. Last night's dénouement, in which Luther sportingly offered to immolate himself with a can of petrol in his cunning bid to finesse the robotic killer Nicholas Millberry (Steven Robertson), took place in the back of a truck parked, as far as I could tell, right next to Moorgate tube station (Elba and crew on location, pictured below).

I think what I'm trying to say is that Luther works - or more specifically, this second series worked much better than the first one - because it gave Elba his own custom-built ballpark to play in, and he did it with so much force and dynamism that it didn't matter much what anybody else got up to. There isn't even a handful of actors who can manage Elba's scope, from using his physical bulk and glowering stillness to freeze the blood of entire neighbourhoods to exuding gentle avuncular warmth in his scenes with mixed-up, screwed-up Jenny Jones (Amiee-Ffion Edwards, pictured below with Elba).

As it turns out, Elba has been surrounded by a fine supporting cast, even if they have risked being caught in the dark of the leading man's sun. Dermot Crowley's portrayal of Luther's boss, Detective Superintendant Schenk, has been a little marvel of shrewd nuances and fretful tics, while Warren Brown's DS Ripley has skilfully trodden the line between minding his boss's back while being inwardly gnawed by doubts about some of his more scandalous off-piste excursions. On the other hand DS Erin Gray (Nikki Amuka-Bird), though a talented fast-tracker, is disastrously lacking in the kind of political intuition required to scale the force's booby-trapped career ladder.