Frank Harlow, the technical director of <i>Chitty-Chitty-Bang-Bang</i>, poses with the eponymous car.

Frank Harlow, the technical director of Chitty-Chitty-Bang-Bang, poses with the eponymous car.

''THERE is not a moment, even on the edge of the tomb, when I am not slaving for you,'' Ian Fleming wrote to his publisher in 1964.

The best-selling James Bond author was in hospital, felled by his second heart attack in as many months. At the urging of a friend, he began writing a children's book based on a bedtime story his used to tell his only child, Caspar.

Several months later, Fleming suffered another heart attack and died on Caspar's 12th birthday. He did not live to see Chitty-Chitty-Bang-Bang: The Magical Car published.

Surprisingly, the book provoked a strong reaction from critics: some praised its thrilling plot twists while one Guardian reviewer attacked the car itself, declaring, ''I don't care for her much, or the values she stands for.''

Despite the supposed infractions of this immoral automobile, she went on to star in a hit 1968 movie with Dick Van Dyke, then a stage musical. Opening in the West End in 2002, it became the London Palladium's longest-running show before moving to Broadway, where it was nominated for five Tony awards.

On Wednesday, it opens at Her Majesty's Theatre with a cast including Rachel Beck, David Hobson and Alan Brough. The real star, however, is the eponymous protagonist: the car that hovers, swims and flies.

''We're working around the clock to get it looking a million bucks,'' says technical director Frank Harlow.

In fact, it is worth $1.3 million, making it the most expensive stage prop in the world. Even up close - a point at which most props look flimsy - it is a beautiful machine.

''It has lights that flash, speakers for sound effects and electronics to push the radiator out,'' Harlow says. ''There are some pyrotechnics, too.''

Many see it as a children's version of the high-tech automobiles Fleming created for Bond. His inspiration, however, was a real racing car named ''Chitty Bang Bang'' after the sound it made when starting. Built by a wealthy English count in the 1920s, Chitty raced at Hingham Park, where Fleming was a frequent guest.

Of course, only Fleming's car converses with its occupants via a series of honks and flees dangerous situations by sprouting wings and a propeller.

''We use very simple technology to make it fly,'' Harlow says, showing The Saturday Age on the condition it is kept secret. ''The thing is, it really looks like it's flying and we don't want to ruin the magic of that. It would be like watching a movie with a guy in the corner of the screen explaining how all the special effects were done.''

The car is not the only impressive prop: all up, there is $4.5 million of elaborate contraptions including the ''breakfast-making machine'', the ''haircutting machine'' and the evil Baron Bomburst's car.

While the play opened in Sydney late last year, Harlow says it was ''basically an out-of-town try-out for the big Melbourne opening''.

''It's funny watching the audience,'' he says. ''Some of the parents know the story better than the kids because they saw it when they were young, then showed it to their children. As soon as that familiar overture starts, the parents start clapping. They're all going, 'This is the bit where the spies come on; this is the bit where the car flies'.''

mlallo@fairfaxmedia.com.au