Nelly the elephant packed her trunk and said goodbye to the circus. Off she went with a trumpety trump, trump, trump, trump. Come on troops. Lets take check: Finn Bar, slightly ruffled but still on fighting form. Maggie, could do with a full nights sleep but otherwise all in order... Stay here. Dont answer the door.When 22 year old Polly Stenham first hit the scene with her debut play That Face, critics raved, audiences stood and nearly everyone was unified in referring to her as the next big thing. 18 months and many hard hours of labour later, she is back with her latest insight into dysfunctional families and desperate situations. And its even better. In fact, this is the most absorbing and fascinating production Ive seen in years.Finn (Finn Bennett) is seven, Maggie (Bel Powley) is 14 and Eliot (Toby Regbo) is 15. Deserted by their drug addict mother, the three have to cope in a new flat on their own under the constant burden that to reveal their dreadful plight would most likely result in their separation as a family. Eliot fights hormones, and the sudden thrust of responsibility on his young shoulders pushes him close to the edge, while Maggie is hiding the trauma of being the last person to see her mother alive; both are bound together and torn apart by their attempts to protect little Finn and hold what fragments of a family they have left, together.When Finn falls from a pile of boxes and cuts his head open at the end of Act 1, the situation escalates further and nearly all of the capacity audience in the intimate space were moved to tears. A child screaming for his mother in any scenario is a painful one, but this is moving beyond belief. It is undoubtedly made all the more real by an astonishing performance from Finn Bennet who throws all hint of child acting out of the window and gives us total and unparalleled truth. Bel Powley is also magnificent. When she breaks down and is forced to delve into her relationship with her mother in a spellbinding monologue near the end of the play she cries and in those few poisonous hours they would be close.... because what brings you closer than sharing hell their crisis was etched indelibly in my mind. Meanwhile Toby Regbo captures Eliots character with conviction, even though he is a little one pitched at times. Stenham also manages to find sufficient depth to the plot to add some real intrigue to the second act and the supporting characters are crucial in this respect; Eliots girlfriend Cassie (Georgia Groome) and family friends Katie (Caroline Harker) and Roland (Tom Beard) especially when Katie and Rolands relationship is seemingly torn apart by a cruel revelation.This is not a comedy. It is tough to watch, agony at times. But it is a fascinating depiction of how we all crave motherly love and how children cope when put under extreme physical and mental pressure; indeed there is an element of Lord of the Flies about it. When Nelly flees her circus, she leaves behind her a trail of pain, desperation and destruction. tusk tusk is raw, powerful theatre at its best. Do not miss it.