Harper Regan is a play packed full of unforgettable conversations, exceptional acting and brutal honesty. The writing is powerful but unpretentious, the acting real but not forced and the set symbolic, yet claustrophobically realistic. As a whole it is one the most emotive and alive productions I have seen in a long time, with Lesley Sharp setting the play alight in a blazing central performance.

Sharp’s is a type of acting rarely seen on stage; powerful and assured yet also subtle, restrained and impressively open-ended. She tackles the script with imagination and confidence, while still allowing her co-stars to take over in all the right places. The result is some wonderfully balanced scenes, which ebb and flow at a mesmerising pace. As a play it is not exceptional, but as a collection of vignettes it works splendidly; an independent film on stage almost, but one which has more dramatic sense than some overtly theatrical pieces.

Marianne Eliott brings her customary flair and sensitivity to the production with firm direction that pulls the play together, while allowing it to find its own rhythm. Every scene is given equal weight and each is driven by the quirky characters rather than the plot. The story is simple and almost superfluous: after discovering her father is about to die, Regan leaves job, home, responsibility, and sets out to say goodbye. The beauty of this piece is that excepting a devastating confrontation between Harper and her mother, the majority of scenes are deliberately random, touching on common themes but rarely looking directly at Harper’s grief or the trouble at home she is trying to escape.

Most scenes feel like mini-plays in their own right and it makes one wonder why so few plays include genuinely random chat. Freed from back-story, expectation or routine, conversations between strangers reap surprising rewards. It helps that Stephens has created an ideal central character in Harper Regan – a woman so inquisitive and spontaneous, that those she meets give themselves away without realising it. A fine example of this is the charming scenes between Harper and local teenager Tobias Rich (a mature and vulnerable performance from Troy Glasgow), with their unlikely connection revealing a wealth of hidden gems about each of them. The quiet tenderness between Harper and this defensive young boy is striking, and their meandering, light conversations gradually take on a surprising gravitas.

The best and most incisive scenes are the unexpected ones – those that contribute to the sense that this is life unfurling onstage, rather than a play taking its course. A great example comes after Regan’s hospital visit, when she meets a man she has found on the internet. Although Regan and cyber-date James Fortune (a splendid cameo from Brian Capron) are supposedly meeting for a quick shag, their shady hotel liaison contains great depth. There is a tremendous moment near the scene’s close when the two dance slowly across the stage together, silent but for the sound of Capron’s gentle, wistful singing. It is an unspeakably lonely image, as we watch two people struggle to escape the lives they’ve made themselves.

There are a lot of similarly effective moments, which build up gradually and suddenly, unexpectedly reach an extraordinary emotional pitch. This is a play of parts, rather than one booming message, and though Stephens continually returns to the loneliness and moral ambiguity of modern life, his characters always come first. He also has the ability to hold something back so that although Harper is permanently onstage, we haven’t come close to figuring her out by the play’s close. It is a rare playwright who creates characters who live beyond the play, and a rarer actress still who has the guts, sensitivity and humility to allow the space for this to happen. A truly absorbing, fiery and memorable production.

Till 9 August 2008