As Citadel, the final book in her Languedoc trilogy, is published, bestselling author Kate Mosse tells Hannah Stephenson about turning down Hollywood in favour of a British TV adaptation of her bestseller Labyrinth, and her joy at clinching a cameo role in the forthcoming mini-series

STANDING on a hilltop in southwest France, addressing actors John Hurt and Vanessa Kirby, proved a surreal experience for best-selling novelist Kate Mosse.

The 51-year-old author of Labyrinth and Sepulchre, the first two in her blockbuster Languedoc trilogy, had clinched a cameo role as a tour guide at Montsegur in the forthcoming six-hour mini-series of Labyrinth.

“I have a few lines at the end,” she says, smiling. “It’s my first acting role and I’m comfortably sure it will be my last. The actors were both standing with me, looking at me as I was talking. It was an extraordinary sense of my characters coming to life.”

In both Labyrinth and its sequel, Sepulchre, feisty female heroines lead the action. Citadel, the third in the trilogy, also features stories from two eras, following the fortunes of heroine Sandrine Vidal, a young resistance fighter in Carcassonne and her network of women resistantes, codenamed Citadelle.

Mosse was still writing Citadel when Labyrinth – which also stars Janet Suzman and Jessica Brown Findlay (of Downton Abbey fame) – was being filmed.

Seeing John Hurt as a character who appears in both books had an influence on her writing, she reflects.

“It was very odd seeing a character that I’d invented in Labyrinth coming to life and then influencing how he subsequently appears on the page in Citadel. All the time I was writing Citadel, I had John’s voice in my mind.”

The spirit of the book is bang on, she enthuses.

“I cried for the last hour and a half because they’d done it so well.”

The series, which was executive produced by Ridley Scott and his late brother Tony, will air on Channel 4 next year. Mosse turned down the chance to make Labyrinth into a Hollywood movie before the TV deal was struck.

“When Labyrinth became a worldwide hit, we did have conversations with Hollywood but my agent and I didn’t feel you could ever do it justice in a couple of hours.

“Everyone was talking about the male lead, but the leads are women. So we turned down Hollywood.”

All three books are set in Carcassonne, a region of France which she holds dear. She and her husband Greg, a creative writing teacher, bought a house there in 1989.

They used to spend half the year there with their two children, who are now grown up.

“So much of my writing of the last 23 years has been inspired by falling in love with the place.

My husband had lived for some time in Paris. My mother-in-law was retiring and had a little bit of money so we just pooled resources and it seemed a lovely thing to do because we were teachers and writers and having somewhere to go is a lovely way of having a holiday every year.

The minute I arrived, the place felt like home.”

They spend less time there now because of work commitments, so it has become a holiday home.

As part of her research for Citadel, she learned how to fire weapons from the Second World War, receiving lessons at the Ministry of Defence training range at Shrivenham, near Swindon.

“I was shown all the Second World War pistols and sub-machine guns, rifles, the lot. It was the first time I’d ever held a gun, let alone fired one. I was a dreadful shot.”

The eldest of three daughters of a solicitor and teacher, Mosse grew up in Chichester, West Sussex, and was penning stories and plays from an early age.

“Books were a part of everyday life, which is one of the reasons I’m so involved in the library campaign. Children who grow up thinking books are a normal part of life are more likely to be successful in education. For me libraries are the symbol of that.”

Success was slow, and she wrote several non-fiction and fiction books before she hit the big time with Labyrinth in 2005. Since then, her books have sold in their millions in 40 countries.

Women are at the heart of her stories, which are essentially action adventures and, as the Orange Prize founder, women’s fiction is important to her.

“I write adventure fiction, in the tradition of Jules Verne and Rider Haggard. People like stories of active men and women.

“I’ve been lucky and I wrote the kind of book that readers wanted at the time they wanted it. You can’t chase those trends.”

  • Citadel by Kate Mosse is published by Orion, priced £18.99.