The Scottsboro Boys, Garrick Theatre

You come away from The Scottsboro Boys sure of two things: that the next cakewalk you hear will induce queasiness and that the show's director/choreographer Susan Stroman is some kind of genius. This kick-ass West End premiere, now happily transferred from the Young Vic, has a simplicity, a precision, a visceral energy, a choreographic razzle-dazzle that make an art of catching you off-guard.

The story of the Scottsboro nine shamefully symbolises the sickness that once resided (and maybe still does) deep in the heart of American society. The nine innocent black youths were exonerated only last year for a rape they didn't commit but from 1931 through endless trials, incarcerations and disappearing decades, the lives of each and every one of them was systematically dismantled: America, land of the not so free. 

OK, so this story from the dark ages of racial inequality is sadly not so familiar, but what makes this treatment of it so potent and ultimately so uplifting is the context that masters of musical satire John Kander and Fred Ebb and their book writer David Thompson give it. Kander and Ebb's last show together delivers a decisive sucker punch not by inviting us to "come to the cabaret" or to be complicit in the consequences of "all that jazz"  but by inviting us to cakewalk our way to that much-loved celebration of racial degradation - the minstrel show - where the Scottsboro boys will kick up their heels, bang their tambourines, and tell their desperate story with jubilant relish. 

All the while, their presiding puppeteer - the whiter-than-white Interlocutor (the frighteningly genial Julian Glover, second from left in the picture below) - pulls the strings and turns the grotesque parody of black-face on its head by cynically commandeering four of their number to assume the identities of their accusers and their persecutors. 

It is for sure a twist-and-a-half to have two young black men - the excellent Dex Lee and James T Lane - assume the airs of two lily-white southern belles, Victoria Price and Ruby Bates, whose charges of rape set the whole horrow show rolling. And then to add insult to injury by having the virtuosic Colman Domingo and Forrest McClendon act out a gallery of brutal (but oh, so comic) law enforcement officers and incompetent defence lawyers. But that's all part of the "entertainment" in which we the audience are made complicit by simply enjoying it so much. When the Interlocutor says sit, the boys sit; when he says jump, they jump; and when he says, "let's do the cakewalk" (his favourite), they oblige - for a time. As the statistics of injustice rise in hair-raising disbelief, their willingness to participate will surely dissipate. Won't it? 

Kander and Ebb's songs strut and sizzle through the action (hell, let's celebrate the electric chair), not so much picking up cues as creating them: a piquant soundtrack of 1930s southern spice from a band with edge and a whole lot of attitude (musical director, Phil Cornwell). There's an unsettling close-harmony number, "Southern Days", which start out like a gently parodic evocation of the Deep South from the white man's perspective but casually, shockingly, turns on itself with a vision of burning crosses and dangling bodies.

And there's an achingly beautiful ballad. "Go Back Home", movingly attended by Brandon Victor Dixon's dignified Haywood Patterson whose creed, "I don't tell people stories, I tell the truth" is the most supreme irony of all in that it is his voice that eventually shines through the decades. His is the voice of an illiterate who refused to trade admission of guilt for freedom but instead learned to read and write and found within himself the words to carry his truth for all eternity. (Dixon pictured left, by Johan Persson)  

The final queasy twist in this knockout show is the sorry spectacle not of white performers in black-face, which would be (and was) heinous enugh, but of black performers in black-face: a truly shocking parody of their very selves. But it's also the last frontier and, show now over, the performers wipe the grotesque make-up from their faces while the Interlocutor is left floundering as to why they don't hear, let alone obey, him any more.

Throughout the musical, a mysterious woman called simply the Lady (the appropriately named Dawn Hope) - mother of all black sons, an embodiment of black pride - pervades the action. And it is her words - her only words, as few as they are emphatic - that signal the moment of change and bring hope to this paradoxically bleak but also exhilarating tale.

• The Scottsboro Boys at the Garrick Theatre