Review of Consent by Nina Raine at the National Theatre

To call Nina Raine's muscular and probing Consent a courtroom drama threatens to suffocate the piece's inherent depth, which, thanks to its skilfully plotted narrative and careful character portraiture, encompasses much more than your standard crime thriller. For all the legalese and grandstanding about the world of barristers within which most of her characters operate, there's just one brief scene set within an actual courtroom. Raine uses this preoccupation to turn the role of justice and truth back on the audience, who, sat in banked seating in the round are handed the reigns of their own morality in a careful and tightly formulated manner that makes for piercing drama.

Opening on a flat warming for new parents Kitty and Edward, Raine's first trick is to introduce an overriding sense of marital bliss which invites you in to a familiar and rather unremarkable setting, including a charming well-behaved baby that radiates warmth and joy. As the two couples trade mild insults and distract from the champagne-flowing formalities with details of their professional lives, the topic of sex begins to underpin their discussions - a topic that will from then on consume them throughout.

As their personal lives teeter on the brink between truth and lies their professional one brings with it a connection that makes for a cold and stark handling of what it really means to leave your work out of the home. Off-duty they talk glibly and often crudely of their legal cases, many of which involve sexual assault and one of which revolves around an alleged rape in which Edward is acting for the defence and Tim, a close friend and long-time admirer of Kitty, for the prosecution. For their off-the cuff take on their cases Raine shows how it's possible to defend the guilty and the consequences that has, particularly when you're forced to view the world through a process of legal code rather than emotional sensitivity. As details of one case literally invade the group's personal lives with an Ibsen-like morality that confronts and sheds perspective on their own situation, the parallels are neatly drawn.

It's expertly delivered by a committed and fearless cast who together mine a form of naturalism that feels appropriate to both character and situation, never indulging yet blooming at the appropriate swells. Together they make Raine's dialogue bounce; it's never hysterical or over the top, instead they have a command of the language that makes the whole performance feel like a cloudy window into real life. As a group of intellectuals Raine manages to harness the complex neurosis of high achievers, from battling with the body clock in time to have a baby to intellectually absolving themselves from feeling base human emotions at the expense of competitive pursuits.

Anna Maxwell Martin is quietly electric as Kitty, charting the piece's most difficult journey and offering a highly complicated portrayal of a character obsessed with truth, guilt and innocence. She's blunt and succinct in her performance, nothing is redundant or wasted, and as she balances on a fine edge that finally tips she's reduced to a shaken frame. Ben Chaplin is quietly troubled as her husband Ed and affectionately displays how a life absorbed in the judicial system has the potential to drain empathy and remove the importance of saying 'I'm sorry'. There's less meat in the characters of Jake and Rachel, but they're well served by Adam James and Priyanga Burford who offer contrasting moral views and keep the perspectives ever shifting.

Roger Mitchell's direction is clean and efficient moving swiftly and effectively through connecting scenes that deliberately feel disjointed as if suspended in time. He handles split scenes particularly well - some of the most engaging moments of staging see multiple conversations occur simultaneously, adding to the rich texture that Raine develops. Hildegard Bechtler's subtle design serves the piece well, utilising a collection of lights that descend to suggest space and add a delicacy to the overriding situation.

The end result is a meaty and complicated new drama that offers audiences a forum to examine their own morals, truth and faith in the legal system. Raine doesn't attempt to solve problems, that would be too neat and coy; instead she lays a careful foundation for important debate and exploration. Anyone who has ever been in a relationship will see elements of themselves reflected back at them, and in the alternating handling of the sexual misfortunes you're forced to delve into the uncomfortable. It succeeds because it doesn't spell things out or attempt to draw lines by moralising, yet it's this absence that makes this a vitally formidable new drama.