He was 40. She was 12. It wasn’t right, but despite what they said he was never “one of those”. Ray has done his time. Now, 15 years later, he just wants to get on with his life, but today Una has found him again.

From Thursday, York Theatre Royal and company-in-residence Pilot Theatre present David Harrower’s two-hander Blackbird, winner of the 2007 Laurence Olivier Award for Best New Play, in the intimate Studio Theatre.

Directed by Pilot associate director Katie Posner, this unflinching portrait of two people trying to make sense of their difficult past will be performed by George Costigan, last seen on the Theatre Royal stage in November 2008 in Arthur Miller’s Death Of A Salesman, and company newcomer Charlie Covell.

Katie invites you to join lost souls Ray and Una in the staff room of Ray’s workplace as the audience are asked to form their own opinions on a subject that Harrower deals with in a balanced and non-judgemental way.

“It’s incredibly well written, hyper-realistic, beautifully written in fact,” says Katie.

“The premise is that Una confronts Ray 15 years after they had a relationship when he was 40 and she 12, but what’s initially perceived as an incredibly black-and-white situation then makes you question your judgements over that situation. “That’s what excites me about this play. It challenges you about something that you would say is wrong, but what’s exposed is a love story that you present in a raw sense, and I feel really privileged to be directing it. I truly believe this play is faultless.”

George Costigan says that when confronted by such a subject matter he “can only play what Ray wants and Charlie can only play what her character wants”. “What comes together is theatre. We can all intellectualise about it but it comes down to theatre.”

You cannot step back from the issues in the play, as an actress, asserts Charlie. “Actually, you take a step in. I knew in advance what the play was about and had preconceptions, and then you read it and think, ‘how could we do it?’ but you leave that behind and play the truth of it,” she says.

Katie rejoins: “Both Ray and Una have questions they want answering and at the end they’re still left with shed-loads of questions, and so are the audience.”

George makes a significant point. “Being in it is not as difficult as watching it because we’re not making moral judgement on it,” he says.

“I would say this is what theatre does best. You take an issue, you illuminate it and you leave the audience to make their mind up – and bizarrely I expect it to be really entertaining.”

• Blackbird runs in The Studio, York Theatre Royal, from Thursday to November 12, at 7.45pm plus matinees at 2pm on Saturdays and 2.30pm on Thursdays. An after-show discussion with the cast and director takes place on November 9. Tickets: £7 to £12 on 01904 623568 or yotktheatreroyal.co.uk