Pondering what makes for the nadir of the showbiz biopic screenplay is a yawning chasm that we had best not peer into, lest we fall in and plunge into a rich madness that can barely be described in words. I mean, it's only been fifteen years since Beyond the Sea, and I'm still not sure I've entirely recovered. But I will say this: cradle-to-crave biopics, on the "Dewey Cox needs to think about his entire life before he plays" model, are obviously trash, and all of the worst of the worst that the biopic form can provide shall be found there. Generally, though I've been a lot mellower towards the other biopics, the ones that study how a very famous person dealt with one specific problem over a tightly constrained block of time (the Jackie model, we might say, if we are feeling generous; the My Week with Marilyn model we might say, if we are feeling irritable). With that on the record, I am willing to go out on this limb: Judy, a new story about Judy Garland's 1969 run of concerts in London, is close enough to the nadir of the showbiz biopic screenplay on this other model that I feel comfortable talking about it that way.

Really, it is a wall-to-wall disaster. The film has been adapted by Tom Edge from Peter Quilter's 2005 stage play End of the Rainbow, about which I know almost nothing; but I do know enough to suspect that Judy has sucked all the guts out of the play, flattening and de-personalising and trivialising it until it barely manages to function at all. Fuck, I don't even know if it does function. I mean, I saw the 118-minute film based on the screenplay with my own two eyes, so I guess for a given definition of "function", it must function, but it doesn't want to.

The film opens on the set of 1938's The Wizard of Oz, where teenage Judy (Darci Shaw) is having poison cooed into her ear by the manipulative, abusive Louis B. Mayer (Richard Cordery). It is the first and truest sign of Judy's dysfunction that this doesn't end up doing anything. We revisit young Judy I think four times across the course of the movie, and we learn all sorts of horrible things about her adolescence: how she was hooked on pills by the studio, how the studio gave her an eating disorder and sexual dysfunction, how Mayer possibly raped her but the film makes certain to do no more than just leer in that direction for a quick second. None of this ends up informing the rest of the film. She's a pill addict, yes, but it takes a line of dialogue to establish that. And there's a quick one-off gag about eating cake that's an explicit call-back, though not one that has the emotional resonance that the film supposes it does. Everything else - the lost childhood, the defiant swimming pool excursion, the friendlessness, the confusion between pubescent young woman and ageless pre-adolescent - just gets swept away the moment after we see it. It's not even the usual tawdry biopic Freudianism of "Judy suffered as a child and this destroyed her ability to be an adult". It's "Judy suffered as a child. 30 years later, she sang some songs whilst drunk", not even doing the hackneyed work of stitching all that together.

Meanwhile, in 1968 and 1969, Judy (now played by Renée Zellweger) has to deal with her hostile ex-husband Sidney Luft (Rufus Sewell), who believes, in accordance with all the available evidence, that she's an unfit mother to their two (anachronistically) young children. To scrape up some money to fight back at him, she takes that job in London, and the vast majority of Judy finds her drifting from one performance to the next, sometimes drawing enough energy from the audience's exuberant love and enthusiasm to feel good about herself, sometimes needing to steel herself with pills and alcohol, and sometimes steeling herself so much that she can't make it all the way through a performance. There's not, for the record, a dramatic scenario here. "Judy has to fight for her children" puts in appearance like it thinks it might be the dramatic scenario, but on a scene-by-scene basis, that's not really informing anything. Mostly, the plot of the film is just what I said a moment ago: Judy Garland sang, and sometimes it was easy for her, and sometimes it was hard, and sometimes she couldn't do it at all.

I concede that there exists a viewer, and perhaps many of them for whom this is sufficient to be engaging and interesting, and I'm damned if I can understand why. Judy comes as close to being about nothing at all as I think a movie could come without tipping into actual experimental filmmaking, and no way something this soullessly robotic in its pursuit of Oscars can be plausibly described as "experimental". It is the biopic impulse stripped bare of anything but its most craven aspect: famous person A existed, and famous person B shall now re-enact A's behavior for your edification as a fan of A, or B, or both. Well, I am quite a large Judy Garland fan and no fan of Renée Zellweger at all, and I was not in any way edified. I was generally bored; I was occasionally excited by the way that director Rupert Goold woke up to stage the performance numbers, all of them in a suitably different style, and at least two of them clearly thinking about how Judy's mood in that moment could be literalised in the amount of zippy energy (or lack thereof) put into the camera choreography and editing pace. I was sometimes frustrated, and once entirely pissed off, when Judy goes off after one show to have homemade omelets with two aging gay fans, a moment that couldn't possibly be more pandering in its treatment of "gayness" as a sort of sexless personality quirk that largely manifests as being a Judy Garland fan.

Anyway, none of this is the film. The film, as you've likely heard lives entirely within Zellweger's performance (and also in Jany Temime's terrific costumes, though there's only a very fine line between the performer and the clothing in some scenes). And she is, to be sure, pretty good. She doesn't look very much like Judy Garland and she doesn't sound very much like Judy Garland when speaking, and we already knew from the evidence of Chicago back in 2002 that she can't sing worth a goddamn. But what she's good at is acting like the character in the script, a desperate addict who realises that her life is fucked beyond repair and that she has had a part in fucking it, whether the devils at MGM deserve the blame or not; but also a consummate professional who really adores singing and sharing the energy that radiates from a captivated audio; but also a 47-year-old woman aware that the audience probably has a vision of her from a much sprier and more lithe time in her life, when she had a steadier voice. The panic and the pride, the self-doubt and the showman's sense of uninhibited glee, are all constantly co-mingling in Zellweger's performance, which involves her whole body (the way she gives into the musical performances is pretty swell) and not just her showy facial and vocal affectations. Is it Judy Garland? No, not really. But is it a strong version of the "Judy Garland" whipped up by this dog's breakfast of a script? Yes, and far better than that script deserves. And this comes from a viewer has has genuinely admired Zellweger maybe twice in her whole career before this. I would be a filthy liar to say that Zellweger makes Judy worth watching, but at least she makes it endurable, and that's honestly a pretty huge achievement.