Blackbird at Shed 6, Wellington

Paula Arundell and Peter Kowitz play an older man and a younger woman reunited.

At the start of 2005, David Harrower told me about the play he was writing for the prestigious Edinburgh International Festival. He had just gone through an about-turn and ditched his first draft with its roll-call of 18 characters. Throwing it in the bin was difficult, he said at the time, but he had started again, trying to write a lean two-hander that would focus entirely on the central dilemma: the reunion of an older man and a younger woman 15 years after the under-age affair that put the man in prison.

"I thought for the Edinburgh International Festival I should have a cast of no less than 30, but mid-December the whole thing shattered and I was left with two characters," recalls the Scottish playwright. "I realised I was building this huge structure but there was only one thematic kernel that I needed which was between these two people."

At that point, it was a full 10 years since Harrower had become Scotland's biggest theatrical export with his debut play, Knives in Hens, translated into more than a dozen languages, staged in 25 countries and given around 80 professional productions worldwide. I idly speculated whether his newspaper name would ever change from "David (Knives in Hens) Harrower".

"That day will come," he promised.

A matter of months later, he was proved right. In August 2005, Blackbird opened in Edinburgh with Roger Allam and Jodhi May as Ray and Una, trying to come to terms with the sexual affair they'd had when Ray was a grown man and Una was just 12.

Peter Stein's production was an immediate hit. The Scotsman called it "mighty and timeless", the Guardian said it was "a riveting study in sexual obsession" and the Daily Telegraph welcomed it as "the most powerful dramatic two-hander since David Mamet's Oleanna". When the production transferred to London, the reviews were even more ecstatic, leading to an Olivier Award for best new play in February 2007, pipping to the post Tom Stoppard's Rock 'n' Roll and Peter Morgan's Frost/Nixon.

A month later, it opened off-Broadway in a production starring Jeff Daniels. The New York Times called it "a drama that promises to be the most powerful of the season".

By this time Blackbird had been seen in Berlin, Vienna and Helsinki with productions lined up everywhere from Chile to Japan. Now Australian star-turned-director Cate Blanchett has staged the two-hander to similar acclaim for the Sydney Theatre Company where she recently became joint artistic director with her husband, Andrew Upton.

"Blackbird is shocking, compelling and morally challenging," said the Australian newspaper, praising Blanchett's "great sensitivity for the rhythms and silences of Harrower's spare, fragmented but theatrically poetic dialogue".