A FANTASY author from Grappenhall has left judges spellbound after her debut novel was named Best Book For Teenagers by Waterstones.

Sally Green picked up the award at the Children’s Book Prize event at Waterstones in Piccadilly for her book Half Bad on the same day that its sequel Half Wild was published.

The 53-year-old's young adult fiction series is about a boy named Nathan and his struggle for survival in a hidden society of witches.

Half Bad was published last year and is now available in more than 30 countries setting a Guinness World Record for 'most translated book by a debut author'.

The saga is also set to be turned into a film series after Twilight's producer Karen Rosenfelt snapped up the rights.

Sally, a former accountant, started writing in 2010 when she found some time on her hands when her 12-year-old son Indy went to school.

She found some of the inspiration while taking walks in Lumb Brook wood after dropping Indy off at Broomfields.

And a story began to take shape in her mind even though she had not written fiction since her O-Levels.

Melissa Cox, head of children’s buying for Waterstones, said: "Half Bad is a hugely assured fantasy debut. It’s full of vivid imagery, relentless action and a hero everyone can root for.

"It’s begging to be adapted for the cinema, but the images it conjures in the reader’s head are more than a match for any CGI Hollywood can offer."

Sally added: "The whole thing has just been amazing. I still have to pinch myself and remind myself how lucky I am to have Penguin as a publisher. It's thrilling.

"I still get excited when I see my novel on bookshelves."

Half Bad was pipped at the post for the overall title of Waterstones Children’s Book of the Year. That honour went to Roy Biddulph for his picture book Blown Away.

Sally's prize was a cheque for £2,000 as well as ongoing support from Waterstones with her novels on sale at the company's network of more than 275 bookshops.