It is an almost inconceivable Royal Court main stage scenario: a group of middle-class young professionals gather for a New Year’s Eve party in an oak-panelled country retreat and tear each other apart.

Michael Wynne’s new play comes across as a “Big Chill” variation with a few bitter twists that leave Kate and her friends gasping for air while the ghost of a hooded monk peers through the window.

Kate (Jessica Hynes), a budding writer, has booked the gig after a traumatic break-up and rebound reunion with long-ago boyfriend Carl (Rupert Penry-Jones), an out-of-work actor married to a thrusting, self-obsessed television producer, Rebecca (Rachael Stirling).

They are joined by travel writer Ben (Alastair Mackenzie) and his flaky new girlfriend – they met yesterday – Laura (Charlotte Riley). In a bizarrely Ray Cooney-style opening sequence, Kate prowls designer Robert Innes Hopkins’s old priory - vaulted walls and light-up stuffed deer heads - while a secretive man in black – the hooded monk? – pops on and off with a Sabatier kitchen knife.

This sets up a farce expectation that is literally in shreds by the end, after Carl and Rebecca’s marriage is laid bare, coke-sniffing compounds the effects of hours of drinking, a fancy dress interlude goes wrong, an iPhone is trampled to bits and the Sabatier features in a wrist-slashing suicide bid.

Sounds like Alan Ayckbourn in the raw? In a way, it is, but Wynne’s sharp, funny writing and Jeremy Herrin’s exceptionally well acted production ensure total authenticity so that by the end the play feels positively radical in this main stage bastion of the cutting edge.

Hynes’ Kate, a character in turmoil after the death of her mother and a miscarriage, is relying heavily on “best friend” Daniel, a willowy gay architect played with quivering sensitivity by Joseph Millson, who weakens momentarily with the intrusion of a local, non-monastic pick-up (Nick Blood).

The play is a giant step for Wynne, who first surfaced on the Court’s young writers’ programme fifteen years ago and co-wrote the beautiful, touching movie My Summer of Love based on ex-RSC publicist Helen Cross’s affecting novel of the same title.

His control of situation and character is impressively mature, and the performances of Stirling as a media bitch and Riley as a dangerously impulsive, sexy outsider are nothing short of revelatory. It’s the most surprisingly conventional play in Sloane Square in a very long time: a really strong draught of seasonal bad cheer.