For every million debut novels that quickly disappear without trace, there’s a smattering of first books which propel new authors into the literary stratosphere.

Right now, everyone’s talking about The Girl In The Red Coat by newcomer Kate Hamer, a 50-year-old creative writing graduate, wife and mother-of-two, whose quiet life in Cardiff may never be the same again, should her debut take off as quickly as pundits have predicted.

“I try not to think about being on the verge of a bestseller,” says the genial former TV and radio producer. “Of course it’s exciting, but I want to concentrate on what’s on the page every day. I just try and think of the writing.”

There’s already been a huge amount of interest from film companies, vying for the rights to this compelling story of an eight-year-old girl who is abducted by a family of drifters, religious fanatics who take her across America claiming she has healing powers, offering to lay her ‘healing’ hands on any disabled, desperate or deluded audience willing to pay for the privilege.

It’s told in two voices – that of the kidnapped child, Carmel, who is wearing a red coat when she is taken, and that of her distraught mother Beth – in alternating chapters, each slowly learning to cope with their painful, displaced lives.

“It’s been described as a crime book and a thriller and a coming-of-age novel, but in one review, somebody described it as a 21st century fairy tale, and I think it’s that description more than anything else that I really like,” says Hamer.

“I grew up on Grimm’s fairy tales and I even have a print of Little Red Riding Hood from when I was growing up. She’d strayed from the path.

“I just had a strong image of a girl in a red coat standing in the forest, and all I know is that she was lost. One night, I sat up and wrote the first chapter.”

“I could see it being made as a film because of the imagery,” she continues. “When I’m writing, I almost see it as a film in my head. But I haven’t got as far as to see which actors would be in the roles.”

The idea of featuring a group of religious fanatics as the abductors was inspired partly by her knowledge of a distant relative, religious prophetess Joanna Southcott, who believed herself to be pregnant with the new Messiah at the time of the French Revolution.

She attracted quite a following and it gave Hamer an interest in cults, although she’s quick to point out that she was brought up an Anglican in a far-from-fanatical environment and remains open-minded about religion.

“I did some research into healing evangelism,” she explains, but is reluctant to elaborate on whether she thinks there’s anything in it. “I don’t like to discount anything altogether. I’m not religious in a particularly conventional way, although I’m really interested in religion. I’m a person that’s looking for answers.”

Born in Plymouth, the daughter of a Royal Navy engineer and a primary school teacher, Hamer is the youngest of three sisters. They’re an artistic family – her mother writes short stories, her eldest sister writes plays and the middle sister is a sculptor.

Before pursuing writing, she studied history of arts at Manchester University, married her husband Mark, a gardener, and had two children, and also worked in independent radio and television as a researcher and producer, on a variety of documentaries.

“I always found time to write in between. I always had that impulse. I’d get up early in the morning to write. Then, when the kids got older, I thought, ‘I’ve just got to do this’. It was mostly short stories and some poetry, but at that point, I didn’t get anything published.”

Once the children had grown up, she completed a creative writing MA at Aberystwyth and also did a Curtis Brown creative novel-writing course, which introduced her to the world of agents and editors.

Soon enough, she secured an agent and had publishers knocking on her door. Faber editor Sarah Savitt was so impressed with the novel, she visited Curtis Brown to make an offer of a two-book deal in person.

Looking back, Hamer says she couldn’t have done it without her husband.

“He’s been so supportive. He always said, ‘If it’s what you want to do, you have to go for it’.”

She’s already three-quarters of the way through her second book, which she says is a coming-of-age novel, a “strange thriller” with a strong female character at its heart.

As she embarks on a nationwide book tour, her career may be going in leaps and bounds, but she remains remarkably calm and grounded.

“My ambition is simply to produce work that I’m pleased with, and that people really want to read.”

n The Girl In The Red Coat by Kate Hamer (Faber & Faber, £12.99).