Leading Article: Why Jurassic Park is a monster achievement

FORGET the dinosaur-sized meal being sold at McDonald's. Never mind the video games from Sega and Nintendo, the computer software from Microsoft, the toys, bedlinen, posters, key rings, badges, door plaques, breakfast cereals or swivelling office chairs. It is the fact that a Cardiff hairdresser has started offering Tyrannosaurus Rex haircuts which proves beyond doubt that Britain is set to join Japan and America in succumbing to the fever of Steven Spielberg's dinosaur film, Jurassic Park.

Anyone who wonders at the film's success - it has already earned back its costs four times over in the United States alone - should start by asking a child of five. For it is at just such an early age that many children draw their first dinosaur; and only a little later that they first hear how scientists know dinosaurs once walked the earth and later became extinct. In the emotions, dinosaurs occupy a twilight zone between fantasy and fact: more exciting and terrifying than elephants or tigers, but infinitely more vivid than creatures of fiction.

When the Natural History Museum in London opened a new dinosaur exhibition last year, people queued for three hours to get in; dinorabilia now account for half the sales of the museum's shop. Staff say the famous hall is 'heaving with people' even before the opening of the new film.

Yet Mr Spielberg and his backers have been lucky as well as canny. The plot for their film - a bestselling book written by Michael Crichton - started from the premise that scientists could reconstruct dinosaurs from fragments of their DNA, and could find those fragments in the veins of mosquitoes that sucked their blood before being fossilised in amber. When Mr Crichton wrote his novel, the idea seemed far-fetched; yet in the very week of the film's US premiere, the journal Nature published an account of the finding of Tyrannosaurus Rex blood cells in a mosquito fossil. While making the film, Mr Spielberg insisted on the poetic licence of having velociraptors a little bigger than scientists believed they had in fact been; sure enough, later excavations revealed bones that brought his outsize beasts back across the line between fact and fiction.

But if Jurassic Park is a success, it is so because Steven Spielberg is a businessman as well as an artist. Gifted with a child's fantasies and an adult's attention to detail, his directing is about project management as well as about imagination. Among the dollars 60m it took to make the film were several millions spent on high technology: only with the help of California's most talented software engineers and robotics scientists could plausible dinosaurs be recreated on the screen. Films like this, after all, are commercial exports as well as cultural ones. Those who are tempted to sniff at the mass-market appeal of Hollywood should reflect on the fact that it provides many skilled jobs of which other countries would be proud.