Once upon a time, there was a Grimm tale about a witch who lured children into her tasty gingerbread house ...

and then ate them. Two hundred years after this scary story appeared in print, we still evoke echoes of Hansel And Gretel when we warn children "not to accept sweets from strangers". And now, just as we are all set to guzzle sweeties by the fistful, Scottish Ballet are preparing to take us deep into the forest with a brother and sister who don't realise how horribly evil the nice lady is who's offering them candy kisses. Could this be the first ballet with an implicit health and safety warning?

A small plate of biscuits is all the sweet temptation on hand during a break in rehearsals when artistic director/choreographer Christopher Hampson and designer Gary Harris plunge into talking about the forthcoming premiere without giving too much away (although they would like everyone, whatever their age, to know that this new version of Hansel And Gretel has a thoroughly happy ending).

"For us this is a story about transformation," says Hampson. "Not just the transformations that you get in dreams or in the magic of fairytales - though we do have those too. Our version has the kind of transformations that can happen to people in real life, when they go through a certain kind of experience. And I think that's as much of a happy ending as the parents finding Hansel and Gretel safe and well, while the witch ... well, the witch doesn't have such a happy ending." Ding dong! the witch is ... you'll have to wait and see.

Back to the beginnings, however, of a project that Hampson flagged up in September last year when he came into the post of Scottish Ballet's new artistic director. He said then that he wanted to use his staging of Hansel And Gretel as a starting point for outreach programmes that would involve communities and individuals all across Scotland.

"We wanted to know what people thought and felt about the story," he says. "But more than that, we wanted them to discover what goes into making a ballet. Instead of us rocking up and showing people what we'd already put together, we took the opportunity of bringing them in on the process of creating a story-board, characters and design ideas. And the feedback we got, from all ages, was inspiring. There are things in this Hansel And Gretel that I'm sure I thought of doing, just because something in a piece of writing or art work caught my eye." And indeed, prominently attached to the pinboards in his office are some of the children's drawings from various outreach sessions.

Gary Harris, meanwhile, already knew just how fascinated Hampson was by the Hansel And Gretel story. During Harris's stint as artistic director of Royal New Zealand Ballet (between 2001 and 2010) he commissioned various works from Hampson - but even though they'd often talked about how to do Hansel And Gretel, it's only now they can join forces to make it happen.

"It does feel a bit 'at last!'," admits Harris, "because there were all these ideas that we'd played about with over a pint - everything from Texas Chainsaw Massacre to Disney and all stages in between. It's one of those stories that works on so many levels. It reaches out all across the board, to adults and children alike because it's a journey of discovery. Regardless of the consequences - even without knowing what the consequences might be - Hansel and Gretel head off. It's the story of how we learn, and we learn by making mistakes. Through errors of judgment. It is dark, really dark. But it's not the Texas Chainsaw Massacre, no."

In fact Hampson and Harris have set their production in the post-war years - 1950s or possibly early 1960s - when austerity was giving way to spending and getting items such as a fridge or a television changed how people lived. Sweet rationing had also ended - even so, not everybody could afford to buy chocolate or caramels as an everyday treat. The Witch is definitely on to a winner with her generous sugary hand-outs.

"It was also a time when children had a lot more freedom," says Hampson. "They could go out and play until it was dark, run wild in a way that doesn't happen nowadays. Parents now are very protective - you could say over-protective. And we have touched on that in this version."

He explains that when the audience first sees Hansel and Gretel, they are more or less prisoners at home. The Witch, in glamorous disguise, has stolen away all the other children - this brother and sister are the only two left. "You can understand why loving parents would want to keep their children safe," adds Hampson "and yet those restrictions are what make these two feel 'to hell with this' and run away to find their friends.

"But they are terribly vulnerable. Hansel's always got a teddy with him. He really clings on to it, which is not necessarily a good thing. Gretel always thinks she's right. But taking her brother on this journey in the first place - was that wise? For me, it's how they deal with the outcome of these decisions that brings about the most important transformations."

He expands on this, saying "at the start, Hansel and Gretel are these squabbling little siblings who really annoy each other. This alters to them being absolutely dependent on each other and having to work together to survive. In a way, they find themselves and they find each other. It's a transformation of character that is probably one of the biggest challenges for the dancers, because Hansel and Gretel might grow up a bit because of their adventures, but we still need to see them as children."

Mind you, a rehearsal of the dream-scene, where Hollywood glamour is the name of the transformation game, soon reveals some of the other challenges Hampson has woven into his choreography. Busby Berkeley could, if necessary, re-take his spectacular routines. So too could Fred and Ginger as they faced the music and danced. But as Engelbert Humperdinck's score rolls out, there is no room for even a split-second error in the timing because it's not just the dancers who are swooping and soaring, the set is also shifting and moving as the Witch's banquet to die for materialises.

Harris has been able to flex his design muscles for this fantasy moment. He chuckles that a visit to the fabric store "really made me feel like a kid in a sweet shop. And working with the dancers has been wonderful. For instance, Eve [Mutso] starts off as a very glamorous witch, so for one of those costumes I'd be draping these soft materials on her, and she'd go into character right before my eyes. And suddenly you see how a design idea is going to work."

It hasn't been all silk and satin, however. "We wanted the townspeople to look normal," Harris continues. "So we have been tracking down as much retro clothing as we can, browsing through Oxfam rails and clicking on eBay. We are getting there.

"Some of it looks fashionable again!"

A transformation of sorts has also been taking place in terms of the music. "It's the Humperdinck opera," says Hampson. "Well, maybe 80% of it, and definitely not in the order that you probably know. Richard Honner, our principal conductor, has done a brilliant job of making a dance score by pulling in bits of other works, moving the Humperdinck music around so as it follows our story - which is quite different to the one in the opera.

"It's a totally new music arrangement, specifically created for a new ballet. And it's very much a first, because no-one else has ever done Hansel And Gretel professionally before. I couldn't believe it. It's been such a popular, well-known story for, well, centuries - but no-one's made it into a classical ballet. For me, it's a new and special experience, because I've made this work on dancers that I know, and have been working with for over a year now. That's a luxury that you don't have as a freelance, even when companies commission you to come back. This is our Christmas adventure together - how exciting is that?"

Scottish Ballet present the premiere of Hansel And Gretel at Theatre Royal, Glasgow from December 10-28 before touring to Edinburgh (Festival Theatre, January 8-11), Aberdeen (January 15-18) and Inverness (Eden Court, January 22-25), www.scottishballet.co.uk