‘Mummy’s got your number. You’re a little shit, aren’t you . . .” So says Eva, the hard-nosed mother in one of the most unsettling books in years. And the terrible truth? She is right. He is. But was her son born evil or did her loathing make him so? We Need to Talk About Kevin is a gut-wrenching novel that, deservedly, scooped the Orange prize last week. Kevin’s mother — Eva — is that rare woman who dares admit that fundamentally she often hates her son, and blames him for trampling all over the romantic side of her hitherto perfect marriage. And that is even before he murders half his class in a Columbine-style massacre.

The book, by Lionel Shriver, a London-based American — she changed her name from Margaret Ann at the age of 15 — was rejected by 30 publishers and its author says she was close to giving up. But her story became a cult hit in New York where childless career women sent it round to friends by taxi.

They took it as affirmation: it’s okay not to want children and if you do have them, it’s okay not to love them. And if they do murder half the school, it’s okay because it’s not your fault.

No wonder the sisters who judge the Orange prize for women’s fiction liked it. But the author, as we shall see, has too nimble an intelligence to write mere feminist propaganda. So while we have not seen such a psychotic fictional baby since Marmaduke in Martin Amis’s London Fields, we gradually wonder at Eva’s culpability — particularly when she hurls her young son across the room.

Her husband says of the uncritical love he lavishes on their boy: “I do what I can to make up for your coldness.” And coldness, or at least coolness, is certainly there in the author. You can see it instantly in her icy eyes. “Taking care of a toddler is so dull,” she says. “I don’t think you can be fascinated by their building with blocks.”

Shriver is an amusing woman, but she does make jokes where others fear to talk. Recalling her days as a babysitter she laughs about the impossibility of hushing a squawker. “I had not discovered the baby shaking route,” she says. “Oh, I could have knocked their brains against their skulls . . .”

There is little more boring than parental party poopers, but even I struggled to laugh at that one. Shriver — who splits her time between London and New York with her jazz drummer husband — is, in case you hadn’t guessed, childless. Might it be different if the child is one’s own? “That is what everyone says,” she smiles, “but beware of what everyone says.” She points out how the smugly mated play down the sacrifices of parenthood, and fires well-aimed arrows at our Kids R Us culture, where every adult conversation is abandoned to fetch little Johnny more ice cream. She seems mighty clued-up for a dinky. “My brother is a good source,” she explains.

So does she never regret not having children (she is 47)? “I cannot honestly say I do. I have led the kind of life I like.” Indeed, there is hardly a continent where this nomad hasn’t lived.

A child would, she avers, have been like an unwelcome house guest. “It would be an imposition, and I hate being an imposition.” Hmm, at the risk of lurching into pop psychology, might all this say more about her upbringing than about child-rearing generally? She admits her parents were so happily married that she often felt in the way. Her father was a “highly ambitious” Presbyterian minister who wasn’t around much. Her mother started a theological career just as Margaret Ann changed her name to Lionel. Both parents were politically active liberals and sent their daughter to a school that believed in independent study. “Most of the students were on the stairwell getting stoned while I was in the library,” she remembers.

She was left to her own devices, so grew up free of constraints, but also of cuddles. “It was a good childhood. I learnt to play, and I am still playing,” she says. “My only regret is that my company was not wanted more.” Ouch. But only her father is rebuked: “There is a very thin line in my family between God and my father.”

If she sounds rather masculine, she bridles at reports that she changed her name because she wanted to be a boy. “That is reductive and simplistic,” she scoffs. “But I did want to be my father — that is, instead of one of the worshippers, I wanted to be the formidable one. It took my parents a long time to recognise the scale of my ambitions, and the rest of the world has made it very easy to ignore the scale of those ambitions because I wasn’t realising them.”

Blimey, this is quite an ego. It is her right to lead any life she chooses, of course, but this childfree, fun-seeking, turbo ambition can seem rather narcissistic. Even, well, childish. To the probable dismay of some of her feminist fans, she agrees. “Yes, there is something deeply wrong about this notion of living your life purely for its own sake. You could have one generation (without children) that has a wonderful time, going out to restaurants and holidays in France. Then the human race disappears.”