There hasn't been an original new play as gripping, provocative or ultimately startling as David Harrower’s aptly harrowing Blackbird in years. Not since Festen left me shaken, sobbing and stirred has a play taken an audience on such an intimate rollercoaster journey into an irrevocable settling of old, long suppressed scores and festering sores as this one does; while that is high praise indeed coming from me since I seriously believe Festen to me amongst the greatest events of my theatregoing lifetime, that took its story from a prior existing film, rather than the original story put forward here.

Intriguingly, though, both revolve around illicit relationships that occurred many years before the plays themselves are set: a father with his young twin children in the case of Festen, or a 40-year-old man with the 12-year-old daughter of a family friend here. And just as a family birthday celebration ignites an irrevocable night of reckoning in Festen, so a reunion of the two parties to the relationship in Blackbird some fifteen years later – after he has served a six-year prison sentence for his crime and is now settled in a new town with a new identity and in a seven year relationship, but is tracked down by her to the factory he works at – becomes a forum for the unravelling of unfinished business between them.

Even if David Mamet’s Oleanna wasn’t mentioned in the programme, you might also find yourself also remembering that incendiary play and how it toyed with the various positions that you might adopt towards it; but Blackbird is a far more compassionate and less obviously manipulative play. It may seem odd to say that, since paedophilia isn’t a tactful or tasteful subject, but Harrower makes no excuses or apologies for it, either; however, without judgement on either person, he simply makes us party to the bond that formed between them and the catastrophic consequences it has for both that made it so deadly and dangerous.

The play is given shattering life and dramatic detail in a production by veteran director Peter Stein that distils its extreme, oscillating emotions to their essence. Even if I could have done without the occasional mood music that intrudes to underscore certain scenes and thereby seems to be prompting an emotional response rather than letting it speak for itself, it is performed throughout with the kind of bruising integrity that makes for an evening of otherwise undiluted and harrowing power. As Roger Allam and Jodhi May progress from a watchful wariness with each other and mutual resentments at past pain inflicted, their mutual anger and passion eventually erupts into the open with a mesmerising intensity. This is a play that detonates with a rare theatrical charge; don’t miss it.

-- Mark Shenton