At its most powerful, theatre has a directness and honesty that can feel like a punch in the gut, delivering a blow that will send you out into the cold winter night reeling and shaking. In complete defiance of jolly seasonal programming, the new play by Jack Thorne is one such occasion.

The action takes place entirely within the confines of a bathroom complete with all the mod cons, including fully functioning bath and toilet. However, as any fan of Alfred Hitchcock knows, it is within these confines that we are often at our most vulnerable and indeed as Marian and David shed their clothes, we very quickly become witnesses to an exposure of an altogether more complex and troubling kind.

From When You Cure Me at the Bush to the hugely successful This is England series, Jack Thorne has revealed himself to be a master at dissecting the human heart with unflinching honesty. He puts human beings under the microscope with a compassion that never ever sits in judgement. In Mydidae however, which takes its title from a family of flies, we follow one particular couple who seem to take us to a whole other level of searing home truths.

We watch with increasing discomfort as Marian and David casually brush their teeth, run their bath, check themselves in the mirror or comment on how their wee seems to smell of asparagus. Gradually, almost imperceptibly, we are introduced to the binds as well as the deep fissures lying under the surface of these two damaged and fragile people. The sense of sadness and anxiety increases over the course of the hour until you are led to a final scene that shook this audience member to the core.

What makes all of this not only bearable but completely transfixing is the unmistakable honesty of the writing (Marion has a speech asking about her first experiences that made me want to whoop with delight) and the stunning naturalism of the performances. In Vicky Jones’ immaculate production, Keir Charles and Phoebe Waller-Bridge deliver performances of the highest calibre. There is no place to hide in a play such as this and these two superb, fearless actors are stunning in conjuring up a relationship that is increasingly toxic but seemingly inescapable. Seeing this production a few days after Michael Haneke’s Amour, I couldn’t help but be reminded of that film’s similarly frightening, rigorously unsentimental and profoundly moving depiction of a relationship in crisis. Amour may be focusing on the end stages of a lifetime spent together but these two brilliant young actors have a comparable magnetism. I can think of no higher compliment.

As I have suggested, Mydidae is not for everyone and is certainly not fun for all the family or perhaps a great option for a first date but I can’t remember the last time I was so blindsided by a performance and in it’s sheer courage, it’s a major shot in the arm and essential viewing.

-by James Fielding