It will come as no surprise to audiences even casually familiar with the work of these three women that RUNT is a political beast, a work of seething anger at social injustice and marginalisation. Their collaboration on the 2016 play SHIT, which had a return season in this same theatre in 2019, dealt with women at the bleakest fringes of our cities. Dee and Wilks’s collaboration for InFlux at Theatre Works in 2016, Animal, also shares some DNA with this show, in the intensity of the physical movement, in the refusal to flinch in the face of brutality.

Wilks’s unnamed runt, scrambling to escape that sack like a kitten at the bottom of a well, sucks in great mouthfuls of air on release, complaining that there is nothing else for her to suck, no maternal nourishment, no love left for the last of the litter. What follows is a painfully funny listing of all the siblings who came before. ‘Boy. A basher. Boy, boy, twins. One who won’t shut up and one who won’t say a word. Girl. Pretty. Curls. Boy. A great big boy. A basher.’ There must be twenty or more of them, before the penultimate child, ‘born with teeth’, who recalls Richard III. Then finally the runt, small and ugly and useless.

Nicci Wilks in RUNT (Pier Carthew)

It’s a superb performance, full of jutting jaws and wide-eyed anguish, alternating wildly between desperate hunger and coiled defiance. Wilks is particularly good at tonal control, an ability to shift the mood of a moment at whim, and the effect is highly unnerving. One sequence in particular demonstrates this skill, and it involves nothing but a wail. It begins with pathos, a genuine note of grief, but soon it morphs into the forced, manipulative bawling of a needy child. It is hilarious, and has the audience laughing warmly. But somehow, Wilks shifts gear a third time and the cry becomes something entirely different, a complex howl of horror at the inequity of life. All these shifts in a single wail.

Dee sometimes feels like the only director good enough to bring this playwright’s work to fruition, and again she demonstrates her power over the text and the actor’s body. Sequences of levity punctuate the more aggressive provocations in the script, which gives a lilt and bounce to the pacing, but then nothing is allowed to impinge on or obscure Cornelius’s dramatic intentions. When the play turns violently towards agitprop, and Wilks confronts the audience directly, Dee lets the implications sink in. Again, it shows a refusal to flinch from the central idea, which recalls Lear’s epiphany on the heath, his determination to ‘expose thyself to feel what wretches feel’.

The simple set design by Romanie Harper, with its suggestion of a nineteenth-century anatomy theatre, is effortlessly effective, and Jenny Hector’s lighting design is precise and supple. Kelly Ryall’s sound composition is – like hiswork on Animal – profoundly unsettling, throwing up images of trains rumbling underneath the floor of the theatre, or great plagues of insects humming in unison, or flies buzzing around a corpse. Every aspect of the mise en scène is highly considered, proof of a strong dramaturgy and unity of vision.

Nicci Wilks in RUNT (Pier Carthew)

There is a crystallisation of thought and intent occurring between these artists that is thrilling to watch, but there are new elements too. Cornelius has honed her talent in a way that has paradoxically freed her up: her mastery of cadence, of the rough-hewn poetry of Australian slang, is well established, but in Runt she seems to be experimenting with formalism, playing with rhyme and repetition in ways we have not seen from her before. It doesn’t blunt her advocacy; if anything, it underscores it. Portraying this young woman as someone preternaturally gifted with language, a sage of rhetoric and allusion, makes her somehow more powerfully aggrieved. It is rare to see Australian socialist theatre stray so far from naturalism – RUNT is worlds away from Daniel Keene’s oeuvre, for example – but it is wonderful to watch.

Make no mistake, RUNT is as fiery and fierce a work of activism as any of Cornelius’s previous plays. The central character may be a cipher – standing in for all the marginalised, the impoverished and the forgotten members of our society, those we kick and belittle and ignore – but under Dee’s electric direction and an utterly vivid performance by Wilks, she also feels lived in, like someone we might meet or avoid on the street. At one extraordinary point in the play, she turns all her rage and hunger, her resentments and disappointments, onto us, insisting ‘I want what you’ve got. I’m coming to take it.’ She mentions the cars and the houses, the ‘Dolces and Gabbanas’, but the choices and the opportunities too. ‘The foot in the door.’ The runt may want what the rest of us have, but her needs are more basic still. Nourishment. Love. Attention. Is that so much to ask for?

RUNT continues at fortyfivedownstairs until March 7. Performance attended: February 25.

This project is supported by the Copyright Agency’s Cultural Fund.

Correction: An earlier version of this article used the wrong pronoun when referring to Kelly Ryall.