The class war degenerates into foul-mouthed tirades and stomach-churning violence in Laura Wade's robust adaptation of her own coruscating stage play.

Posh originated at the Royal Court Theatre in London in 2010 and was revived two years later in the West End, painting a vivid portrait of a fictional dining clique akin to the Bullingdon Club at Oxford University, which once included David Cameron, George Osborne and Boris Johnson in its notorious ranks.

Lone Scherfig's film, retitled The Riot Club, packs a similar emotional wallop to its stage-bound predecessor, detonating pent-up testosterone and tempers with horrifying repercussions.

Wade has fleshed out key protagonists and excised some scenes entirely to reduce the running time by 40 minutes.

There seems to be a greater emphasis on the fledgling romance between the most likable male character and a down-to-earth northern lass (Holliday Grainger), who is dazzled by the dreaming spires and gushes, "Being at Oxford is like being invited to 100 parties all at once - and I want to go to all of them."

The Riot Club is not a party most of us would wish to attend. But that's the point.

Alistair Ryle (Sam Claflin) arrives at Oxford, hoping to emulate his older brother, a former president of the titular fraternity.

This hush-hush 10-strong dining club honours the memory of its libidinous 18th century founder by boozing to excess at an annual dinner, trashing the venue and paying for the damages out of their trust funds.

Given his lineage, Alistair is almost certain to catch the eye of Riot Club president James Leighton-Masters (Freddie Fox).

However, it is dashing classmate Miles Richards (Max Irons) from more humble stock, who steals Alistair's thunder and arouses the homosexual yearnings of influential club member Hugo Fraser-Tyrwhitt (Sam Reid).

Alistair and Miles pass initiation and are inducted into the ranks alongside Harry Villiers (Douglas Booth), Guy Bellingfield (Matthew Beard), Toby Maitland (Olly Alexander), Dimitri Mitropoulos (Ben Schnetzer) and George Balfour (Jack Farthing).

The students head to a country pub run by Chris (Gordon Brown) and his daughter Rachel (Jessica Brown Findlay), who have no idea of the devastation about to be wrought.

The Riot Club is a sobering attack on a culture of inherited privilege and power in Britain.

Scherfig's film dissects how our egalitarian society is founded on secret handshakes in wood-panelled rooms far from the madding electorate, and you can almost see the venom streaking down the camera lens when one inebriated club member sneers, "I am sick to death of poor people!"

The Danish filmmaker, who previously helmed the Oscar nominated coming of age story An Education, doesn't spare the morally repugnant characters any blushes.

A climactic showdown is just as jaw-dropping in lurid cinematic close-up as it was from the safe distance of the theatre's upper circle.