There is nothing a channel controller likes better than a renewable drama, however improbable the likelihood of yet more killings in a picturesque little seaside town. No sooner had ITV scored a ratings hit with its murder mystery, Broadchurch, than it announced a sequel.

Last month’s 5-part drama series on BBC2, The Fall, set in contemporary Belfast, also attracted large audiences, and its renewal was duly announced just before the last episode aired. However, viewer reaction was much more negative to this seeming piece of opportunism: at least Broadchurch wrapped up its first story, whereas all the loose threads in The Fall remained unresolved at the end of the series.

Yet in many ways the absence of a resolution was one of the strengths of The Fall: indeed, less than half way through the fifth episode it was obvious that the main plot and subplot could not possibly be disposed of in the remaining screen time, especially as clues that would tell the investigators the identity of the central character – a serial killer – were still piling up.

It is hard to believe that a writer as skilled as Allan Cubitt – whose credits include the second series of Prime Suspect – could have originally scripted a version of episode five that gave closure to all the storylines, and then sometime after the airing of episode two, wrote and filmed a new version of episode five. It is clear that the BBC – and its production partners, including RTE – always knew that a second series of The Fall was inherent in the project, subject only to satisfactory ratings for the initial episodes.

The drama’s protagonist is a British detective superintendent, Stella Gibson, played by Gillian Anderson. She is called in by Assistant Chief Constable Jim Burns, played by John Lynch, to inquire into the murder of Alice Parker Monroe, a 32-year-old architect who is the former daughter-in-law of the chairman of the Police Service of Northern Ireland, Morgan Monroe. Monroe is a one-time Unionist MP.

Unknown to Burns or Gibson, Monroe is engaged in dubious business dealings, aided by his son, Aaron, who provides class “A” drugs, high-cost prostitutes and unofficial police protection for his father’s foreign clients. Serving police officers – including a detective called James Olson – help him clean up when clients run into problems.

The PSNI has spent thirty fruitless days investigating the Alice Monroe murder, which is why Stella Gibson has been brought in to review the case papers. Looking at photos from the murder scene, she concludes that Alice’s body has been posed, and that this cannot be the first time the killer has struck. Quickly, she sees a connection with the death of a university lecturer, Fiona Gallagher, some weeks earlier. Burns is reluctant to pursue her theory, but a third murder forces his hand, and he makes Gibson the senior investigating officer for all three cases.

By this time, Cubitt has revealed another side of Stella Gibson. She has a sociology degree. She studied the Musuo women of China, who select their sexual partners for “sweet nights” and “walking marriages”. She engineers an introduction to James Olson when she sees him at a crime scene. She invites him to her hotel room. Hours later, he presents himself for a lengthy sexual encounter. And hours after that, he is assassinated outside his own home.

Yet despite the assassination (which we later learn had no sectarian motive), the recognisable Belfast locations, the distinctive Belfast accents, talk of “taigs”, the riots in the Shankill during police operations and the air of constant menace, this is not a drama about “the troubles”. The Falls Road itself never features. Nor is there any reference to Camus’ “La Chute”.

The strongest clues come from the episode titles Cubitt has chosen: not that these were used during transmission – they can only be found online, accompanying the episode synopses. They are “Dark Descent”, “Darkness Visible”, “Insolence and Wine”, “My Adventurous Song” and “The Vast Abyss”: all quotations from Paradise Lost, mostly from book one. 

So we are in a Miltonic world, even if the original sin that pre-occupies Cubitt is not eating fruit from the tree of knowledge, but what Stella Gibson calls “age-old violence against women – misogyny”. This is the charge she makes to the murderer, Paul Spector, when she finally speaks to him, dismissing his intellectual presumptions and his claims that he and she are really alike in their desire for control.

But it is his presumption that he is somehow above the rules of society that marks him out: a presumption echoed by Aaron Monroe, ex-husband of victim Alice, who believes his father’s connections will protect his corrupt business dealings. Belfast may be few people’s idea of Paradise, but at the end of series one of The Fall, both miscreants – verily, sons of Belial – have been exiled, to the mainland.

The third victim is a solicitor, Sarah Kay, murdered even as she – gagged – and her killer listen to a message from a passing police control checking on her welfare (Spector had broken in and stolen underwear the previous day). To our horror, Spector removes his mask, so that his victim can see his face as he slowly strangles her. We know – and she knows – that the act of unmasking has sealed her fate.

At the crime scene, Gibson notes the posing of the bathed and naked body, the fresh varnish on her finger nails, the likelihood of souvenir photos having been taken, a lock of hair removed as a trophy. She theorises that the murderer seeks power, control and the thrill of stalking; that it’s about intimacy (“what could be more intimate than squeezing the life from your victim?”); that he is creating his own pornography.

What she cannot see is the detail of Spector’s life as revealed to the viewers. He is a bereavement counsellor, married to a maternity unit nurse, Sally Ann, with two small children. Ostensibly, he volunteers on some nights for a suicide help line, which allows him scope for his night-time criminality.

Gibson speculates – correctly – that the man they are hunting is a semi-skilled white collar worker in his late twenties or early thirties, and that his victims are of a type: victims of choice, not chance. What the audience sees is an aesthetic and narcissistic compulsion.

Spector stores in his loft his murder kit and a lovingly wrapped murder book, in which he preserves prizes taken from his victims – such as items of clothing, photos and driving licences. He records his stalking activities – “nothing!!” is one entry – and inserts hand-written excerpts from poems and prose works, adding his own commentaries.

One trophy – a necklace stolen from Sarah Kay – he gives to his 6-year-old daughter to wear. Another – the lock of hair – is found by the 15-year-old babysitter, who occasionally works for the family. Both the babysitter and – bizarrely – the daughter mount disturbingly sexualised performances for him: one in an on-line video, the other in a dance for “duddy” in his front room.

Spector is played by a former male model, Jamie Dornan, who has little previous acting experience. It is a bravura debut. Likewise, the producers, Gub Neal and Julian Stevens, gambled to brilliant effect on a young Flemish director, Jakob Verbruggen, to shoot his first UK drama. Neal, of course, is a heavyweight drama figure, whose previous major series for BBC2, The Last Enemy, was a darkly dystopian take on the surveillance state.

Cubitt says he based Spector on a real “BGK” (“bound, gagged, killed”) serial murderer. But he has added a wide range of intellectual (or pseudo-intellectual?) touches. In his journal, Spector cites ‘The Hollow Men’, by T S Eliot: “Between the idea and the reality, between the motion and the act, falls the shadow”. Spector adds his own riff: “is it the murder or the shadow of the murder that causes the greatest pleasure, the greatest pain?”

Now we understand the removal of the mask as he asphyxiates his victims. Gibson is put in touch with a woman in her early thirties, Rose Stagg. She had encountered some years earlier a powerfully built young literature student who on one occasion almost strangled her to death during sex. There is a subliminal message here for Gibson, made explicit in a colleague’s words: who would ever dream of risking sex with a stranger?

The autopsy on Sarah Kay shows she was a few weeks pregnant. When Gibson reveals this publicly, the impact on Spector is profound. We see him rip up the page in his murder journal about Sarah, including an excerpt he has transcribed from Tennyson’s poem ‘The Princess’: “Man is the hunter, woman is his game, the sleek and shining creatures of the chase; we hunt them for the beauty of their skins, they love us for it, and we ride them down.”

He writes to Sarah’s father, saying he would never have killed his daughter if he had known about the pregnancy: “babies are innocent”. He quotes Nietzsche: “one must have chaos within oneself to give birth to a dancing star”. He concludes: “I show you the last man”.

Gibson predicts that the pace of Spector’s behaviour will accelerate. The second murder was two months after the first; the third less than a month after the second; and with his “perfect kill” tainted, he will be taking more risks and making more mistakes.

He has already identified his next target: an accountant in her thirties, Annie Brawley, who shares the “look” of his other victims. But she lives in the heart of the loyalist Shankill, and the attack goes badly wrong. Annie’s brother is with her when Spector pounces. He kills the brother, but Annie survives – just as Spector has to escape from the arrival of more locals.

The brutality and sexual explicitness of the scenes in the Annie Brawley and Sarah Kay attacks have shocked many critics, especially female ones. The Times accused The Fall of turning sex murder “into a Gucci ad”, featuring a villain with ripped abs posing women’s corpses: “the Rubens of rape” (perhaps an unconscious nod to the Flemish director, who had frankly acknowledged the inherent voyeurism of his realistic shooting style). For the Daily Telegraph, “the violence was so vivid, and the women’s terror so real, that I couldn’t bear to watch”. I confess I found the scenes truly shocking: as they were no doubt meant to be.

Even Gillian Anderson’s “cool luminescence” in her playing of Stella Gibson as a sexually-empowered woman has been condemned as contributing to this “snuff movie in a silk blouse”. No doubt one of the episodes in the second series will be called “Her Pale Dominion”: but Gibson’s ambiguous role in a man’s world is unlikely to persuade the doubters.

As the police routine starts to close in on Spector, he is forced to ask his wife to lie about his night-time movements, after revealing that he no longer volunteers at the suicide line. He admits – falsely – to an affair. His wife is shocked, but not prepared to let her children – she is pregnant with a third – grow up without a father, like Paul: unknowable and disconnected (he spent his childhood in foster homes). They decide to leave for Scotland.

Spector disposes of his incriminating horde of souvenirs, but before leaving Belfast, he decides to call the murder hotline. He identifies crime scene details that only the killer knows. He wants to speak directly to Stella Gibson.

“You think you’re an artist, but your philosophy is half-baked,” she tells him dismissively. “Art is a lie,” he responds, quoting Picasso. “Art gives the chaos of the world an order that doesn’t exist. I’m walking away. Watch me.” “I am – it won’t be over till I stop you. And I know all about you. I know what you did eight years ago when you were a student. I know you have a daughter. When she finds out the truth about you, it will destroy her. It will kill her.”

Gibson is referring to a drawing clearly done by a young girl which had been exposed by forensics as having been imprinted on the sheet of paper Spector used to write to Sarah Kay’s father. We now see that Rose Stagg has prepared a wholly recognisable photofit. We hear that Annie Brawley has regained consciousness. We know that the babysitter has preserved photos of Spector. We recognize that Gibson will start series two with full knowledge of who the killer is: just not where he is. Equally, the complications from the Monroe subplot will no doubt compromise her investigation.

Like last year’s Parade’s End, The Fall was a co-production, though at a lower level of budget. It further demonstrates that the BBC remains uniquely placed to be the lead partner in mounting very high quality drama series of limited duration.

Yet these ventures are few and far between, and the BBC remains very much a second division player when it comes to multi-episode, multi-year dramas, where the US is almost completely dominant. It is ironic that HBO’s massively expensive Game of Thrones should be so dependent on Irish actors such as Michael McElhatton, Ian McElhinney and B J Hogg, when their full range of skills can so readily be enjoyed in The Fall.

Archie Panjabi won an Emmy for her showy role as Kalinda Sharma in the CBS series The Good Wife: here she performs in a much smaller part, as a pathologist, but to better effect.

The BBC needs to make a decisive and principled shift of resources, away from the humdrum volume output that dominates its drama offerings, to at least 50 episodes a year of a £1 million-an-hour long-form renewable scripted drama series.

This is less than it has spent in recent years in disposing of surplus bureaucrats. It is half what it wasted on the Digital Media Initiative. It would do more to restore the prestige and pride of what should be a world-class broadcaster than any other creative endeavour it might otherwise undertake.

Alan Cubitt, Gub Neal and Julian Stevens will no doubt be ribbed by their peers for dressing up their serial killer in intellectual and political trappings to match the elaborate posing of Spector’s victims. But it is a rare drama that has the urgency, control and power to persuade an audience to wait a year for the denouement. The US re-make of The Killing succeeded brilliantly with a second half that more than justified the decision to split the story in two.

Milton envisaged Paradise Lost as ten books. It ended up as twelve. We should not be surprised if series two of The Fall has seven episodes, rather than five. If so, the controller of BBC2 will not be complaining. Nor should we be.