After meeting Amanda Jennings in the flesh, its difficult to imagine her as the author of the creepy psychological thriller The Cliff House.

At 45, she seems cheery and down-to-earth, quite unlike the characters in her books, who are usually nursing a hidden grief or a dark secret.

Set in 1980s Cornwall, The Cliff House features a glamorous London family “the Davenports”, down for the summer holidays, who become an endless source of fascination to their cleaner’s daughter, 16-year-old Tamsyn.

So why Cornwall, not South Oxfordshire, where Amanda lives? “My mother is from Penzance and we spent all our holidays in Cornwall. It’s probably the place where I’m most at home. I would have been 13 in 1986, when The Cliff House is set, and remember those glorious moments on the beach, and the sweep of the coastline.

“But there is also a tension between the locals and the wealthy incomers. Cornwall needs their money, but there is also resentment. I wanted to write about how that affects the local community.

“I have always been drawn to people with difficult pasts. I don’t know when it started, but two of my Cambridge University friends had lost people they loved. One lost her mother at 13 and my best friend lost her brother.

“In fact, I have had a very cheerful life, so I wonder whether there is a survivor’s guilt?” she asks.

“Perhaps we need to explore things we have never had to deal with in real life?

“In my books, there is always some resolution and some element of hope for my characters, so perhaps I am trying to solve the world’s problems by writing.”

Amanda’s charmed life began in Wargrave, on the other side of the Thames from her current home at Binfield Heath.

After Cambridge, she set up a small PR business with a university friend, writing copy for small companies. “The sort of thing you do when you are young and full of confidence,” she says.

“That lasted a year and then I got pregnant. When my daughter was two I got a job as a researcher at the BBC, but the hours were not very regular and I missed her terribly. I wrote a sitcom script and had some fantastic feedback but then I had a bit of a crisis. I had this abject fear that I would have to write comedy for the rest of my life.

“So when I was pregnant with my second child, I gave up my job and just did a bit of writing to keep my brain ticking over.”

Her first novel was rejected, but after the success of her next two books, Sworn Secret and The Judas Scar, also based in Cornwall, she revised it and published it as In Her Wake, which hit the big-time as part of WH Smith’s Fresh Talent promotion.

With her oldest child, Daisy now at university, Amanda can finally shut her study door and write uninterrupted, while her other two, aged 16 and 12, are at school, which you’d think would make life easier.

But Amanda admits it’s as difficult to write now as when the children were younger. “When they were babies I learnt to write with the door open as soon as they fell asleep. I could also write in the kitchen with all three around, and if I was in the car and they fell asleep, I used to pull over and edit. I remember rocking one in the car seat to keep her asleep while I finished writing. But now I sometimes find it too quiet in the house. It’s easier to get distracted by social media or jobs than need doing.”

Amanda did not set out to write bestsellers, but tries to make her characters psychologically compelling, tapping into the current popularity of page-turners with a dark edge: “I’m interested in how humans react to trauma. I don’t believe anyone is wholly bad. If you are damaged, there will be reasons for that.”

Unsurprisingly her next book also has a Cornish backdrop, this time 1990s Newlyn, near Penzance. “Writing books, set in a period I grew up, in the place I went on holiday, is so wonderfully nostalgic it’s almost indulgent,” she concludes.

By Maggie Hartford