The breakfast-making machine has been loaded up with sausages. The flying car has had its daily health and safety check. And the Child Catcher is sharing a laugh with his make-up artist.

I'm backstage at the Alhambra, where there's an hour to go until the curtain rises on a matinee performance of Chitty Chitty Bang Bang.

With thousands of costumes, a 100-strong cast and crew and an array of spectacular contraptions and special effects - not least the world-famous flying car - it's the biggest show on tour.

Guided backstage tours organised by Bradford Theatres give the public chance to go behind-the-scenes. As I discover, they provide a fascinating insight into what goes into a huge production like Chitty, which is mid-way through a two-month run Bradford run.

Audiences have been enchanted by the magical adventures of Caractacus Potts, his children, Jeremy and Jemima and their winged car.

Along with Grandpa Potts and Truly Scrumptious, they're taken to the air on a thrilling journey, pursued by the child-hating Baron Bomburst of Vulgaria.

As I'm led into the wings by stage manager Eddie Davison, the first thing I see is Caractacus Potts' sweet-making machine. It's one of several complicated-looking contraptions I keep bumping into as I make my way around.

There's the hair-cutting machine and the breakfast-making machine, which drops eggs and sausages into a frying pan. "They're all pre-programmed," says Eddie.

I look up and see the windmill, home of the Potts family, with the children's beds at the top of a spiral staircase. A realistic-looking hen sits at the top, ready to drop eggs down a shute for the breakfast-making machine. "We call her Marjorie," smiles Eddie.

Squeezing past Grandpa's outhouse, I find Truly's motorcycle, the Child Catcher's horse and the derelict racing car that turns into Chitty. A pair of stilts and a couple of bikes are propped against a huge birthday cake.

Sitting on a shelf is Truly's picnic hamper, the Baron's teddy bear, bags of Toot Sweets' and a jar of dog biscuits for the show's 11 highly-trained dogs which all appear in one scene. Also on the shelf is an original 1929 copy of Pictorial magazine which Grandpa reads as he's airlifted to Vulgaria.

The show involves lots of flying; with several characters taking to the air. Eddie shows me the flying lines, hanging way above us, attached to an automated flying system.

The star of the show is, of course, the flying car. Suddenly there's the four-wheeled diva herself, looking rather unglamorous with a green cloth draped over her. Weighing a tonne-and-a-half, she's a high maintenance leading lady.

"She can be temperamental, but don't let her hear that," whispers Eddie. "We test her flights before every performance. We had to cut a channel into the stage to accommodate the mechanics used to operate her."

When you see the show it's a real thrill seeing the car taking to the air. "It's emotional," says Eddie. "There's something moving about seeing magic' right in front of you. This show suits the Alhambra stage very well. From here we can see the audiences' faces when Chitty flies, they're blown away.

"Because it's such a huge show it takes nearly ten days to set up. But it's fairly straightforward - when everything's going well." At that point there's a loud bang from the other side of the wings. "That was a balloon popping, we tend to lose quite a few of those," grins Eddie.

A couple of dancers are practising the Me Ole' Bamboo routine. Soon other cast members appear and start limbering up. "They do vocal and physical warm-ups before every performance," explains Eddie. Tony Adams, who plays loveable eccentric Grandpa Potts, waves to us as he walks around the stage doing vocal exercises.

Upstairs in wardrobe, someone is busy at a sewing machine and the air is filled with steam from a pile of ironing. There's a staggering 6,000 costumes for wardrobe mistress Sylvie and her team of three to look after!

"It's a very physical show, with wild choreography, so there's lots of wear and tear on costumes. They require constant maintenance," says Sylvie Sargeant-Bennett. "There are 200 shirts to be laundered before each performance. All shirt collars have to be starched and re-pressed.

"There are lots of quick changes, we work with eight dressers from the Alhambra and it's all hands to the deck!"

The costumes are a big part of the show, especially in song-and-dance numbers such as Toot Sweets and the Baron's birthday party. "Every scene has a different look. I just wish the audience could see the detail on the costumes," says Sylvie.

"It's the biggest wardrobe on tour. There are 400 children's costumes alone. The Baroness's are the most elaborate; hand-beaded and lined with feathers and fake fur. Anything that falls off while she's rolling around on the floor has to be replaced."

Kim Ismay gives a fabulous performance as the Baroness, in a great double-act with Ken Morley's Baron.

"My costumes are gorgeous," says Kim, showing me the sumptuous outfits hanging up in her dressing-room. I'm surprised how heavy they are, especially the beaded dress and double velvet-lined coat. A succession of basques and corsets look like they've walked off the set of Moulin Rouge.

"They're quite restrictive, especially with all my movements," says Kim, slipping a beautiful red Thirties-style dressing gown, lined with black feathers, around me. "I get feathers up my nose and in my mouth, as does anyone else who comes near me," she smiles.

Over in Christopher Timothy's dressing-room, make-up artist Helen Williamson is transforming him into the Child Catcher. Ever since Sir Robert Helpman's memorable performance in the 1968 movie, the Child Catcher, who lures children into a cage and kidnaps them, has terrified generations of youngsters.

"He sniffs children out and makes them vanish - it's sinister stuff," says Christopher with a shudder, as Helen stretches a latex bald cap over his head.

"It's an iconic role, one of the most far removed from my comfort zone, and I was very nervous at first. The first time Helen did my make-up I couldn't believe what I saw."

When Helen starts applying pale foundation on his face he fleetingly resembles Gollum.

Helen has done the make-up for several Child Catchers, including Richard O'Brien and Paul O'Grady at the London Palladium. "The process takes about 20 minutes," she says. "The look is a bit less panto' than it used to be."

As she sticks pointy latex ears onto Christopher, then a long nose, he looks increasingly sinister. This is the kindly vet I spent my childhood watching in All Creatures Great and Small - it's unnerving seeing him turning into the stuff of nightmares.

"I loved that role, but it took a while to move on," says Christopher. "My agent used to scream down the phone: He's an actor, not a vet!'"

Helen shades parts of Christopher's face with darker make-up, "to bring out his features." When she sticks black stringy hair on top of his bald cap and he pulls on his black leather gloves the creepy look is complete.

Christopher isn't on stage for another hour. Is it uncomfortable sitting around in all that latex and make-up? "Not at all," he says. "If this was 25 years ago I'd be making myself up. I once sat in Olivier's dressing-room watching him prepare for Othello, he applied make-up to every part of his body then he was polished with a chiffon scarf. It took four hours and he hardly spoke, it was fascinating."

Back in the wings, the curtain has risen and I watch the opening scenes unfold. Tony Adams waits to go on stage - this time dressed in Grandpa's military uniform. The audience chuckles as Kevin Kennedy, alias Caractacus Potts, cranks up one of his wacky inventions.

And waiting patiently in the darkness is Chitty herself, quietly revving up for her grand entrance.

  • Backstage tours are held at the Alhambra and St George's Hall. For details, and for tickets for Chitty Chitty Bang Bang which runs until April 5, ring (01274) 432000.