Imagine your world was a single room. No windows, just a skylight; no greenery but a single sickly plant; no animals except for the insects and vermin that find their way into your prison. This the world that the five-year old Jack shares with his mother in Emma Donoghue's remarkable new novel, Room.

"When I was writing it, I was designing their prison, deciding exactly what I would allow them: yes, television but no internet; yes, daylight but no nature. I was the captor. To look at every thing from the other side is quite a mind-bending exercise," laughs Donoghue.
Room has been long-listed for this year's Man Booker prize, but Donoghue has been careful not to get her hopes up.
"I can't even think about that," she says. "The most I can hope for is to make the shortlist."
Inspired by the case of Josef Frizl who kept his daughter Elizabeth a prisoner in a basement for twenty-four years and fathered seven children with her, in the wrong hands this story with its catalogue of cruelty and abuse could have been little more than torture porn, something Donoghue was careful to avoid.
"What I wanted to write was not in any sense that story," says Donoghue. "I wanted it to be streamlined and stripped down of many of the extra horrifying elements, like the incest, I wanted to pare them away and simplify it so that the book would have some of the qualities of a fairytale or fable. I wanted it to be a less horrifying confinement than any of the real cases."
The novel is written from Jack's perspective and it is his story. Jack's experience of his captivity is not one of horror. Room is instead the story of a childhood lived in a confined space, allowing Donoghue to pose an interesting question: "What's wrong with a childhood in one room? What is the missing element?"
Writing about life in a confined space where very little action can happen is no easy task, admits Donoghue.
"That was one of the very first technical worries I had. I remember a friend saying to me, 'Oh you'll have to decide exactly how much of the book to set on the inside. How much can readers bear?' I was also very aware of how many pages would pass before the first bit of drama. I didn't want the plan to be on page one, because I wanted to convey Jack's sense of a fairly peaceful childhood where every day is pretty similar to every other day, but I knew the drama had to come in quite fast. That was a real challenge."
Having spent all his time with Ma, Jack is perceptive and verbal and an engaging narrator.
"I thought five would be old enough. My son was five at the time so I thought if I give this narrator enough time, he will be able to explain everything to the readers. Once I found a voice for him it wasn't difficult to write – it was a joy.
"I think it's fairly clear that he would be linguistically ahead," she adds, "because there's nothing like having one adult talking to you to teach you language. But physically, he would be cautious about a lot of situations. I look at my three-year old dangling from the monkey bars in the playground and she has a physical freedom that will take Jack quite a while.
"He and Ma have endless quality time together, not just because they have been locked up, but because Ma has been willing to surrender herself to motherhood in this way, in the way that I and most other parents do not. We want to be workers and consumers and friends and lovers, we want all these other identities but Ma has been in a position where only one identity makes her happy so she gives herself over to that. The whole book is a bit of a romance of the mother-child bond really."
Jack has never experienced the outside world, so he knows nothing of it, and believes everything he sees on television is fantasy. After this fifth birthday 'Ma' begins the process of explaining the world to him as she plans their escape.
"I had to drop hints of Ma's misery but yet not have demons in the room. I was tinkering with that very consciously. At every point I thought of the book as Jack's story rather than Ma's story. In the end we have learnt a lot about her but my loyalty was always to Jack so I let things come up at the point where he needed to hear about them or where I thought it was likely that Ma would tell him."
Using Jack as a narrator allowed Donoghue not only to pace the revelations of the abuse Ma has endured, but use Jack's perception to throw the adult world around him into sharp relief.
"I wanted to do that from the start, because I felt that would be a lovely way to question our society if somebody came to it as an outsider not having believed in it before. I wanted the second half of the book to have a lot of social critique so I designed it that Jack would be like a visitor from another planet."
Having had his mother's undivided attention for all his life, Jack notices that while adults pay lip service to adoring their children they seem to not have much time for them.
"I am that adult!" Donoghue laughs. "I'm an author who has written this book about motherhood but I have a daughter that's three and I saw her talking to her dolls saying 'I have to shop for dinner now, don't bug me!'"