Alice Fancourt has, on the surface, got it all. A loving husband, a healthy baby girl.

They all live together with her husband David's mother Vivienne, and David's son by his first marriage, in a rambling country pile.

Alice dotes on her baby Florence, and the child is two weeks old before Alice can bring herself to leave her for the first time and go out by herself. With such a loving, tight family unit around, what could possibly go wrong?

When Alice returns she finds the front door of the house swinging open, her husband dozing in a chair and in the cot in the nursery lies a gurgling, happy infant. . . who Alice is quite sure is not her beloved daughter Florence.

The phrase "psychological thriller" could have been invented for this gripping novel by poet and prose writer from Ilkley, Sophie Hannah.

Alice is distraught enough to find a changeling in the place of her daughter, but Hannah cranks it up another level when everyone else acts completely normally and insists that the baby in the cot is Florence.

The writing in Little Face is taut and Hannah ratchets up the tension like a tourniquet as Alice sinks into a mire of despair, believed to be losing her mind by her husband and written off as suffering post-natal depression by her mother in law.

But Alice has a saviour in Detective Constable Simon Waterhouse, who sniffs something a bit suspect about the whole set-up.

Looking into the background of the family, Waterhouse learns that David's first wife Laura was the victim of a vicious murder at the house.

A man is in prison after being convicted of the murder - but did he really do it? Waterhouse decides to re-examine the case, and meanwhile Alice decides to take matters into her own hands with a little investigation of her own.

Little Face is not simply a crime novel. It is a thorough and deep exploration of the dynamics of an on-the-surface happy family, revealing the seething secrets beneath.

Sophie Hannah makes the leap between her award-winning poetry and her prose skilfully and seamlessly, and while her writing has lyrical echoes of her "other job" it is never purple or unbelievable.

Rather, there is an economy about her writing which adds a dreadful normality to the horrendous moment, especially when Alice is confronted by the awful truth: "The curtains are closed. I look down into the cot and at first all I can see is a baby-shaped lump. After a few seconds, I can see a bit more clearly. Oh God. Time slows, unbearably. My heart pounds and I feel sick.

I taste the creamy cocktail in my mouth again, mixed with bile. I stare and stare, feeling as if I am falling forward. I am floating, detached from my surroundings, with nothing firm to grip on to. This is no nightmare. Or rather, reality is the nightmare.

"I promised David I would be quiet.

My mouth is wide open and I am screaming."

Billed as "every mother's nightmare", Little Face is an accomplished thriller that will appeal to anyone who enjoys a rattling good read but will send especially shiversome chills down the spine of any parent.

Little Face by Sophie Hannah is published in hardback by Hodder & Stoughton, priced £18.99.