The ghostly shadow of Agatha Christie emerges in a dimly-lit garden on a mystery-filled night in Torquay, the birthplace of the queen of crime which is celebrating the 125th anniversary of her birth.

"Do you think it's her?" a young woman asks her neighbor half-jokingly when she spots the hat-wearing silhouette crouched over her typewriter in the glamorously old-fashioned English Riviera town.

Hercule Poirot, the famous Belgian detective she invented, can be seen pacing nearby in Torre Abbey - one of the Torquay landmarks hosting a legion of Christie fans and experts who enjoy a bit of dress-up.

Wearing a blazer and a straw boater at the garden party, Piers Cardon says he is a "super fan".

"I want to get in the atmosphere, to feel the golden age," the 66-year-old retired schoolteacher says.

Cardon and his fellow faithful have descended on Torquay from around the world for the 10-day festival.

Many of the men wear gaiters and coat tails and the women are in pearl necklaces and satin or lace dresses, gathering in the evenings to dance to piano tunes or drink cocktails in Art Deco hotels.

But it is not all about fun, there is also a more academic side to the events. "I want to develop my knowledge about Agatha Christie," says Cardon, who read his first novel by her at the age of 10 and has never looked back since.

At one festival workshop, crime writer Martin Edwards talked about how Christie and her contemporaries set the foundations for the modern murder mystery with the legendary "Detective Club" they created.

At another seminar, David Brawn, editorial director at publisher HarperCollins, talked about the difficult ties the author had with her editors, displaying different covers for her books starting with The Mysterious Affair at Styles (1920).

Among the 100 events at the festival are also theater evenings with performances of some of the 20 plays that the prolific Christie, who died at the age of 85 in 1976, also authored.

"Normally I do not like crime. I detest cruelty," says Veronika Hotowy, a dancer attending a lecture at which attendees laughed out loud at extracts from the witty repartee in Christie's novels.

"But Agatha Christie's are more detective stories, putting the puzzle together. Not cruel at all," says Hotowy, originally from the Austrian capital Vienna.

"There is a short description of the murder, only one sentence. It's a game, you have to use your little grey cells," she adds, using Poirot's famous phrase.

Cardon says today's psychological thrillers bore no resemblance to Christie's whodunnits.

"They want to make things complex, they want you to escape from the normal life," Cardon says.

"Agatha Christie did not do that. She said: 'This is the village, there is nothing complex about it but by observing the village you will see how to solve the murder'," she says. "They are real characters, people you can understand."

Anne Martinetti, a French author and fan, says: "All living writers have read Agatha Christie and have been inspired by her, whether they acknowledge it or not. She invented everything."