Drag Race fans already know that the series’ “queen of all queens” Jinkx Monsoon does a mean Judy Garland impression from her lurid account of a threesome with Dean Martin and Frank Sinatra. This revival of Peter Quilter’s 2005 play puts Monsoon’s Garland in a love triangle instead, caught between steadfast, gay pianist Anthony (Adam Filipe) and opportunistic, soon-to-be fifth husband, Mickey (Jacob Dudman).

It plays out in 1960s London as the decade, and Garland’s life, draw to an end. Quilter divides the drama between private and public, moving from the performer’s hotel suite to her residency at Talk of the Town, derailed by her drinking and a drug addiction that dated back to her teenage role in The Wizard of Oz.

We’re not in Kansas any more – nor Grand Rapids, Minnesota, where Garland grew up as Frances Ethel Gumm. But unlike the 2019 film Judy, which significantly fleshed out Quilter’s play with flashbacks including a miserable 16th birthday party, you get precious little sense of how she was exploited and controlled as a child star. While it also lacks momentum, the script is friskier and funnier than the screenplay, with acidic quips and gratuitous name-dropping and shade-throwing (at theatre queen Agatha Christie no less!) but the musical numbers, orchestrated and arranged by Leo Munby, anchor the emotions in the story. Garland sings Just in Time as an ode to Mickey, fooling herself that he is her 11th-hour saviour, then reappraises the relationship in You Made Me Love You (I Didn’t Want to Do It).

It is pristinely designed by Jasmine Swan who drapes the full stepped stage in white curtains, with a black grand piano at the centre. Swan retains the same black and white palette in the costumes until a theatrical feat mimicking the famous transition to a Technicolor Oz as the band hit their stride under Nick Barstow’s music direction and the flamboyant hues of Prema Mehta’s lighting.

Monsoon has a hoot as a woman who has lost count of her husbands, goes literally weak at the knees when kissing her new beau and melts on the floor like the Wicked Witch of the West. (There are Oz Easter eggs galore.) Elsewhere she hobbles around in one high-heeled shoe while singing into another. Her voice is magnificent, incessantly rising and falling in conversation that veers from combative to caustic but especially in song. An added drawl stretches out some words like the elongated suck of a cigarette that she treats as a vocal warm-up. It transcends impersonation, particularly in the concert scenes, as Monsoon roots each song in Garland’s trauma and has the skill to show, across a single number, the flickering golden quality of her voice, alternately triumphant and tarnished. She gives a deep sense, too, of how Garland was adopting a persona for an hour or two a night.

It’s tremendous casting which also honours Garland’s status as a queer icon, which is underlined in the script by Anthony’s earnest appreciation and Mickey’s homophobic contempt. Though Filipe is touching, both of the characters remain too functional, teeing up her anecdotes, and the hotel scenes grow grindingly repetitive and exasperating, although that’s the authentic terrain of addiction. Despite opening with Monsoon among the auditorium, singing It’s Yourself as if dedicated to us, Rupert Hands’ production never theatrically exploits the sense, explicit in Rupert Goold’s film, that Garland’s everlasting relationship is with the audience. As the inevitable Over the Rainbow finale beckons, and her torch songs match the bygone glamour of this gorgeous, arrested-decay auditorium, you’re left with the nagging sense of what Monsoon would deliver in a full, one-woman version instead.