Until I Kill You, ITV1 review - superb performances in a frustrating true-crime story

The latest true-crime adaptation about a murderous man and his female victims turns its star into a bloody mess on a hospital table, her vital signs flatlining. And that’s just halfway through, with two episodes to go. 

At least the second half of Until I Kill You offers less gruesome generic territory (spoilers ahead): the bungled police investigation of the assault; the sympathetic WPC assigned to the surviving woman, Delia Balmer (Anna Maxwell Martin, pictured below, left); the dangerously clumsy twists and turns of the justice system; the eventual resolution of this sorry saga. But although Nick Stevens’s script is clearly on the side of the angels, there are key elements it doesn’t – can't? – include that undermine its mission to shine light on the case.

The action begins in 1991, in north London, where Balmer, a self-styled Canadian free spirit, is making a living as an agency nurse. She’s what would at the time have been called “kooky”. She lives in a mostly empty, cavernous flat with coloured strips of fabric as notional curtains and a sleeping bag on the floor for a bed, wears hippy outfits (Afghan coat, garish velvet trousers) and has a tendency to idiot-dance in inappropriate places, like the local boozer. Where she catches the eye of a pleasant-looking man at the bar, a chippie called John Sweeney (Shaun Evans, pictured below, right).

Their lightning romance over, he starts lording it over her in her own flat, moving in his pet tarantula and building her furniture she doesn’t want, including a bed. Its purpose will become gruesomely clear. She soon wants him gone (though the span of their relationship seems to have been four years). Meanwhile, over in Amsterdam, a white-haired American man is desperately searching for his beautiful blonde daughter Melissa, who has mysteriously disappeared. This cross-cutting will continue through to the end.

Aside from the Dutch scenes, a couple of short sequences where the police back at the nick talk about Balmer's behaviour among themselves and shots of Sweeney making his way back to London after jumping bail, we are alongside Balmer, watching her closely. She is a loner, insistent on being called a “traveller, not a tourist”, who’s clearly plucky but her own worst enemy when faced with incompetence: “ornery” and abrasive towards the police and social services, liked only by her colleague Leah and a kindly man, David (Kevin Doyle), who moves in with her once Sweeney has been sent down. She rarely speaks to her family, now living in Texas, though has an apparently affable brother there.

Her fiercely independent attitude predictably morphs into crippling mental health issues after the assault – at Sweeney’s first trial she reels off a list of everything wrong with her mental health, from PTSD and anxiety to depression and loss of confidence, a once-intrepid woman scared to embrace a new day. The prosecuting silk predictably plays the male chauvinist sex-card, accusing her of having an S&M relationship with Sweeney and wanting to testify in person that day only so she can see him again. “Why is the law allowed to treat people like this?” she angrily demands. Why indeed.

The story will lurch on almost to the present day – towards the end we see a photo of the real Balmer on one of her long jaunts abroad, taken in 2023. She has survived the conventional cat and mouse game of the serial killer genre, but there were two cats here, one of them British justice. Balmer’s troubles were far from over once Sweeney had been sentenced and jailed.

This is where the gaps in the script start to frustrate. Viewers have to take all the bad moves made by the law here as read, unscrutinised and unexplained. Balmer is a victim many times over, but her plight is made worse by unseen agents, such as the (offscreen) judge who first gives her vicious attacker bail, then the (offscreen) one who hands down a derisory sentence that will make him eligible for parole in nine years. (That judge is useful dramatically, it must be said, for giving the new detectives on the case, led by the ever dependable Geoffrey Streatfeild, a deadline for finding conclusive evidence that will put Sweeney away for good.) Even the police, Balmer is told, can’t believe that sentence.  

But why is it so light? Was it something Balmer said? Was the judge following official sentencing tariffs? What did his summing up say? Is Sweeney suffering from paranoid schizophrenia? If so, how did his condition evade detection? Did the police really reject out of hand the concrete leads Balmer gave them about Sweeney’s confession to her that he had murdered Melissa? Why are his drawings of Melissa's dismembered body dismissed as evidence? 

Why, in short, isn’t Balmer’s case taken seriously enough? Inherent sexism? A mass male misunderstanding of her hostile behaviour? Ill-judged rulings by the CPS? Was the judge at Sweeney’s trial known to hand down this kind of sentence? Have any of these shortcomings been remedied now? The series clearly wants us to be moved by Balmer and to register the injustices, but doesn't give us enough tools to do that with. It isn't enough to say, which the script implicitly does, ah, look, this was the 1990s, when people still had dial-phones, the police had no computing power and women who cried rape were horribly treated – of course she wasn’t taken seriously.

This far into the 21st century, though, with growing insight into the failures of the law, especially the police, in protecting women, we need to understand how and why, exactly, this particular case was so botched. Watching it go horribly wrong isn’t the same thing. For once, I really wanted screeds of end-credit captions explaining where we are now, how the case did or didn’t affect the handling of subsequent cases, what hasn’t changed. 

Maxwell Martin gives a fine, stirring performance, gripped by white-hot anger; you fear for her blood pressure when she’s going full tilt. We can see where her intransigent refusal to appear in court is rooted and can’t understand why the authorities don’t see it too, though we can assume that her “difficult” nature was problematic to unsophisticated male detectives. The only thing that gives concern is her accent, which wanders around the globe much as Balmer does, more Irish-sounding than Canadian at times with a spritz of West Country. Evans, though, is a revelation in his native accent, Scouse: an electrifyingly awful man, chillingly persuasive as a long-haired “nice bloke”. 

These first-rate performances intensify the horror of yet another woman’s experience of extreme violence and the injustices that followed. But we are mostly left as voyeuristic consumers of her experience, struggling to fathom exactly why it happened.

• The final episode of Until I Kill You is on ITV1 at 9pm on Wednesday 6 November. All episodes available on ITVX
• More TV reviews on theartsdesk