Rarely have I changed my mind about a play as much as I did over this, Sudden Impulse's version of The Maids. While I was watching it, I hated almost everything about it: its grandstanding sexual deviancy, its relentless lack of subtlety, its scarcely-credible and seemingly over-wrought plot. But at some point between that night and the following morning, the penny dropped. This is a play which exists to provoke disgust – and the vehemence of my reaction is the measure of its success.

The real disgust isn't at what we see on stage, but at the social structures highlighted by Jean Genet's 1947 script. At the heart of Genet's story is a cruel juxtaposition: the two household maids of the title live within a decadent world, yet are brutalised by their callous and abusive employer. Violence begets violence, and "Madame's" mistreatment of her maids seems to have turned them into sociopaths. We see them rifling through her wardrobe to find props for a sado-masochistic orgy, all the while plotting to kill her. But the line between fact and fantasy is not an obvious one – and this intended revenge may simply be a make-believe device the housemaids use to survive.

It's a fallacy to think that older generations were shocked at the thought of sex, but it does make sense to wonder if a 1940's script can still be provocative in the no-holds-barred Edinburgh Fringe. Well, yes: it can. Some of the sexual content feels more titillating than disturbing – I rolled my eyes when Madame appears and immediately removes her clothes – but the BDSM punishment the maids inflict on each other is depraved in an altogether different way. This isn't a game between consenting adults, but the vicious outpouring of those who know no better, whose self-image and self-worth is entirely defined by the abuse they receive.

In Fringe veterans Sudden Impulse's interpretation of the story, the all-female cast of characters are played by men. Louis Hayward is particularly striking as Madame; it's a tribute to Fay Rusted's work on make-up that I was genuinely surprised when he took off his dress and his true gender was revealed. He captures both Madame's casual cruelty and her high-living dissolution, a contrast which fuels the anger underpinning Genet's social critique.

As the maids, Saul Bache and Sam Bates are convincing and horrifying in equal measure, repugnant in their twisted power-play yet inviting sympathy for the psychological damage which has brought them there. Disturbingly however, the physical damage they inflict on each other seems to be partly for real – with a much-brandished riding-crop leaving obvious marks on the actors' bodies. On one level I respect the commitment that shows, but I'm still uneasy with it; if we say that we're okay with seeing this on stage, then I wonder where it's all going to end.

Whatever your views on that point, it's certainly a perturbing capstone on a generally unsettling play. The Maids isn't an easy work to get your arms around, and it takes thought and time before its true messages emerge. But Sudden Impulse have done full justice to Genet's script – with an adaptation that's initially repellent but, ultimately, shocks in all the right ways.