Posh, Royal Court Theatre

When artistic director Dominic Cooke took up his new post at this venue in 2007, he said that he wanted “to look at what it means to be middle class, what it means to have power, what it means to have wealth”. Although this comment caused a lot of fuss, with die-hard Royal Court fans imagining that he was about to betray the theatre’s tradition of staging plays about low-lifes, Cooke’s programming has managed to balance gritty underclass dramas with plays about the rich and privileged.

Based on those exclusive all-male Oxbridge dining clubs, of which the Bullingdon Club is something of a market leader, which announce the toffness of their members with all the subtlety of an inebriated roar, Wade’s Riot Club sharply outlines the ugliness of this type of institution, with its ridiculously wealthy members braying their prejudices before embarking on their destructive, drunken smash-’em-ups. Yes, it’s not just the poor chavs who binge drink.

Set in a faux-Regency room somewhere outside Oxford, beautifully evoked in Anthony Ward’s colourful and claustrophobic design, the play introduces us to 10 young men, members of an elite undergraduate dining club, who believe that they have a right to rule. The play shows how an evening of harmless fun — spiced up with misogynist comments, hearty hurray swearing and some disillusioned drivel about the modern world — turns into a really ugly incident, which will haunt these boys forever.

The sharpness of Wade’s writing is demonstrated not only in her deft depiction of upper-crust attitudes but also by her understanding of the testosterone-heavy dynamics of this group of overgrown boys. These guys, despite their bulging wallets, have never left the playground. Only James, the club’s president, is mature enough to have made plans, which the others deride, for life after Oxford.

Chief of the braying pack is Alistair, who is granted the best speeches, laced as they are with a mix of venomous contempt for modern life and a nostalgia for the past glories of the aristocracy. He’s the one we love to hate. And the one who appears as a sinister political puppet at the very end of the play. Other memorable characters include Guy, who wants to be president and seeks to realise his ambition by amazing the other members’ taste buds, and Harry, who arrives just after a fencing match — still dressed for the sport. They are joined by George, Toby, Ed, Hugo, Miles and Dimitri.

Like a metaphor for the nation, the old traditions of the club — which suddenly materialise in front of our eyes in a marvellous and ghostly coup de théàtre — sit uncomfortably next to more recent innovations, just as the members sport iPhones as well as archaic waistcoats. At the same time, these young bloods turn out to be pretty inefficient, ineffective and cowardly. It’s the common people, represented here by Chris the landlord and his daughter Rachel, that seem to be the most balanced, reasonable and grown up.

You can’t fault the timing of this play, nor the precision and imaginative flair of Lyndsey Turner’s vivid production, with its superb use of music and slow-mo climax. The cast of 14 are all good, with Leo Bill particularly impressive as Alistair and Joshua McGuire equally strong as Guy. Daniel Ryan’s Chris provides a sound contrast. Posh is a pretty hot word nowadays — provocative because of all the fuss about David Cameron and his cronies being public-school toffs — and this play feels like a key cultural moment that seems to accurately take the temperature of the times.

• Posh is at the Royal Court, London SW1 until 22 May
• Find Laura Wade on Amazon
• Check out what’s on at the Royal Court this season