You shouldn't judge a book by its cover – and you shouldn't judge a play by its title, either. Yes, Work Makes You Free was inscribed above the gates of Nazi concentration camps; and yes, this play's set partly in a modern-day Jobcentre. But no, playwright Michael Ross isn't drawing an offensive parallel, and no, it's not a crass attempt at humour either. When you find out why the play is called what it is, it's as nuanced and clever as it is outrageous – and that proves the hallmark of Ross's virtuoso script, done full justice here by a polished and highly entertaining production.

Work Makes You Free is made up of four essentially separate monologues, though they're interspersed and eventually intertwined. There's Adam, the high-flying minister at the Department for Work and Pensions; Kirsty is an advisor in one of the Jobcentres he controls. Jane has a well-paid job at Canary Wharf, while Willow – the most overtly comic of all the characters – is the "co-founder and co-artistic director" of a right-on theatre company, and spends the first part of the play gloriously enthroned on a yoga mat.

With the exception of Kirsty, these characters are all amusingly annoying, but they're all surprisingly likeable too. Even the Tory minister is far from a bogeyman, and the forces that shaped him are treated with a measure of sympathy and respect. If anything, it's the Guardianista Willow who bears the brunt of Ross's satire; Laura Pieters plays her with a perfect blend of superiority and self-absorption, prompting me to quietly ask myself if it would really be all that terrible if she were forced to get a job in Asda after all.

And beneath these well-balanced questions of political policy, there's a subtler theme at play: about how dreams can fade in the face of practicality, and the disappointments of life can overcome you. There are plenty of spiky in-jokes for creative types in the audience to enjoy, but Miranda Evans brings a stoic poignancy to Kirsty, whose hopes of making it as a musician have stuttered and soon will die. And Emily Bates' City worker Jane comes into her own later in the play, as her extravagant rants at society around her prove to have a very human – and almost forgivable – cause.

So, the subject matter's sometimes dark, but this is still a very funny production. All of the cast have impeccable timing, but special mention must go to Nicholas Stafford as Adam – who can use a moment's pause or a casual glance to wring unexpected hilarity from a mundane-sounding line. That timing, too, extends to the lighting; designed by Charlotte Gowers and operated by Louie Renna, it crisply picks out the individual characters, blending beautifully with James McKendrick's direction to build dynamic images on a sparsely-furnished stage.

There's a twist in the ending which I couldn't quite get my head around, and the music which punctuates a few of the scenes felt random and distracting to me. But those are tiny flaws in a generally top-class production – and when it pauses, briefly, to expound its own political thesis about the value of the arts, it feels like that privilege has been earned. Sometimes startling, sometimes thought-provoking but always enjoyable, Work Makes You Free is an unexpected highlight of the VAULT this year.