Luther: The Fallen Sun film review — Idris Elba’s detective decamps from BBC to Netflix

At this point, Luther is about two-thirds of the way through the life cycle of a prestige TV show-turned-franchise. With no plans from original backers the BBC to grow another season, Idris Elba’s grizzled, determined detective has been repotted in a standalone film. But the formula — DCI John Luther hunts down yet another sadistic murderer, in this case a psychopath played by Andy Serkis — is limp and underwatered, like the weird haystack of fake hair they’ve pinned on to Serkis’s head to make him look sinister.

New hosts Netflix have poured in a fair wodge of money, with locations not just in London, Luther’s usual stamping ground, but also in Iceland (standing in for Norway). There are also beefier, grittier stunt sequences. Yet it all feels like a last flowering before the next step in the cycle, the point where old Luther needs to change career or move aside so that younger, cooler characters can come aboard and spice things up.

For now, writer and series creator Neil Cross deploys all the crime-show conversational clichés, from Luther being reprimanded by superior officers for not doing things by the book to having him earnestly promise a distraught mother (not just once but twice) that he’ll find her missing child, and so on. There’s even that old favourite, an interlude in which our hero is sent to jail and must escape to put things right. Yeah, saw that in Paddington 2, thanks.

To be fair, it must be hard to get the blend of familiarity and innovation right. So, as with earlier seasons, the film delivers plenty of nauseating violence, albeit described more than shown. Like a dumbed-down version of Michael Haneke’s Funny Games, viewers are made to feel somewhat complicit in the torture Serkis’s character inflicts on his victims because — just like the spectators who pay to see the killer’s dark web live-stream show — we keep on watching, fascinated by this theatre of cruelty.

Earlier seasons dabbled in the same territory, with cannibalistic killers and women murdered in especially gruesome ways. Cross also recycles from season one the bent-copper device, planting a colleague working within the force who is secretly in thrall to the bad guy. The only key element missing this time is Ruth Wilson’s silky psychopath-cum-love-interest Alice Morgan who spent so much time in the series kittenishly needling and flirting with Luther by turns.

★★☆☆☆

In UK cinemas now and on Netflix from March 10