Maybe don’t call off the Oscars just yet but it’s got to be worth a trip to the bookies to whack a tenner on Renee Zellweger.

She is fabulous as Judy Garland. I mean, she needs to be, otherwise any film called Judy doesn’t stand much of chance. You’ve got to get all that tremulous vulnerability and all that belting virtuosity, all at the same time. If you don’t deliver that, you’re not doing Judy and any viewer who knows anything about Judy would spot it a mile off.

But Renee nails it. She teeters and she wobbles, physically and vocally, which is just how you want your Judy at this late stage of her career, when a stint in London at the Talk of the Town represents a scraping of the career barrel, the gutter of the yellow brick road. As she says: “It’s just too damp to rehearse.”

There’s a great sequence of addled Judy being gotten ready, shoved into a dress and a taxi and then  shoved on stage and into the glare and Zellweger’s body ratchets into gear, like a marionette being lifted up string by string. The legs are spindly, the arms frail, the eyes pinched. She’s not in Kansas anymore but there’s showbiz in her veins and she can still deliver a belter.

In Rupert Goold’s movie, Zellweger’s Judy is a wounded animal. She’s a Hollywood star trapped in a dank, brown London of cold phone boxes, smoky pubs and dripping alleys. It’s supposed to be 1969 but it might as well be the 50s. She can’t Get Happy, merely put on a brave face.

The action flashes back to her childhood under the bullying of Louis B Meyer, to a fake 16th birthday party held on the set, or to a mocked-up diner date with Mickey Rooney where she isn’t allowed to touch the burgers or the fries.

She can make you laugh but she can break your heart and Zellweger makes the most of the tragedy and the pills, of the desperation in the voice and the eyes. Her child-like joy at the visit of a ne’er do well next husband (Mickey Deans), her craving for the vitamin injections.

There’s much to like here but I should state that this is a typically British film about this very late, very sad period in Judy’s life. Zellweger’s is such a star turn there’s barely room for anyone else to shine – Jessie Buckley, so promising in Wild Rose, can’t raise her young game as Judy’s assistant. Michael Gambon’s Bernard Delfont is a bit part although Andy Nyman sparkles delightfully and briefly as a ‘friend of Judy’ whose dreams come true at the stage door when his idol asks if he knows anywhere to go for a drink.

The film could have done with some more oomph in the incidentals, and maybe a few more laughs amid the tragedy. The Hollywood flashbacks look dowdy and cheap, betraying the project’s roots as Peter Quilter’s stage play End of the Rainbow. Such theatricality feels a pity, although perhaps it’s intended to make a larger point about the budgets shrinking and the pictures getting smaller, or something. That’s giving it a big benefit of the doubt. (I should probably refrain from noticing there’s a hint of Mrs Overall about this Judy – once that thought creeps in, it’s hard to get back on track with the whole Oscar narrative…)

But no, it would be flippant to deny the full beam, film star wattage of Renee Zellweger here. She’s unstoppable, seizing her big chance back in the spotlight with another role that will define her post-Bridget Jones career.  Remember that was another London-set performance where everyone talked, so unfairly, about her weight? Her Judy is another remarkable physical transformation that sees her now whittled down to become the part, and thus become the movie.

This is a Judy where you’ll always remember her songs and her fragility, the bony hands, the pursed lips and those pained, painted eyebrows, constantly curving, rising upward in hope only to fall, like a rainbow.