Five Daughters, BBC One

Five Daughters is “based on the personal testimony of those most closely involved”: family, friends, the last people to see the women alive. What we are watching - the story of the murder of five sex workers in Ipswich - has the stamp of truth. When one girl missed her appointment at the methadone clinic, her mother tried to collect her prescription for her.

The mother, played by Sarah Lancashire with the washed-out complexion of the terminally worried parent, would in effect have been a script consultant. The same went for the episode’s climactic scene, in which Anneli Alderton (Jaime Winstone), not long out of Holloway, cut and dyed her hair peroxide, argued with her mother and disappeared off into the night, never to be seen again.

The task of writer Stephen Butchard was to craft all this humanising testimony, much of it no doubt partial, presumably even self-serving, into drama. Thus Five Daughters has elements of the police procedural, with Ian Hart playing the colourfully named DSC Gull on whose patch the terrible events unfolded. The first episode made a decent fist of shaping the randomness of disparate lives into something like a linear narrative. In the interests of tidiness, Butchard has done things like delete all references to Anneli's child, for example. Occasionally the dialogue took on a writerly aroma. Anneli told her brother that an old friend of hers called Gemma (who was about to become one of the victims) is “still pretty, still fucked. Pretty fucked.” People only talk like that in drama.

The drama is thus far at its strongest, and what feels like its most authentic, when it fixes directly on the impact of drugs on its users. “I want bright eyes,” Gemma (Aisling Loftus) told the boyfriend who every night walks her to the red-light district so that they can both afford to score. “I want my hair to smell nice.” He turned to look at her like any baffled bloke ill-equipped to soothe a woman's inner fears. “You smell fine,” he said over his shoulder. A scene in which they were interviewed by an addiction counsellor was also beautifully shaped. What do you love most in the world, he asked. The crack or each other?

Mining the motives of these girls must, in the end, be down to guesswork. Why any of them were on drugs in the first place is not confronted. The mothers who shared their story were presumably none too keen to look within and ask themselves the question, or at least share the answer in public. There weren’t any fathers about, that’s for sure.

Philippa Lowthorpe, who began her career in observational documentary, has shot it all with a tactful awareness that these were real women once, rather than synthetic products of a storyboard. The odd aesthetic flourish has crept in. The bodies were mesmerisingly filmed, like Gormley statues sprouting horridly faceless and inert in woods and rivers.

Butchard, meanwhile, has done his best to ration the dramatic ironies. Characters do have a habit, like Anneli’s mother (Juliet Aubrey), of saying things like, “I think she’s going to make it this time.” But then maybe she did say that, just before Anneli, apparently grieving the loss of her friend Gemma, went fatally back on the game.

There is a debate to be had about the morality of processing these girls’ sorry tales as what, in the end, must adhere to the grammar of fiction. After all, years of addiction to detective drama have taught viewers one thing over everything else: you could make it up.