Leading Article: Star sponsorship reveals its perils

IT HAD seemed a perfect match. Pepsi Cola, keen to sell its sugary brown concoction all over the world. Michael Jackson, a man with a direct line to millions of the world's children, and a private funfair in the grounds of his Californian mansion. To the people at Coca-Cola headquarters in Atlanta, Georgia, they must have seemed an unbeatable foe in the fizzy wars.

That was 1984. Today, almost 10 years and as many million dollars later, the Jackson tour is curtailed with the star, by his own account, addicted to painkillers and broken by the psychological pressure of allegations of sexual abuse. And Pepsi has been dragged unwittingly into the negative publicity. The situation raises a question: was the advertiser merely unlucky, or are international celebrities simply too unstable to sell a global product?

There are exceptions. Before he helped to sell Mercury phone calls, Richard Branson flew a balloon across the Pacific with sponsorship from a Japanese soft-drink company. He was too polite to admit that its product, improbably named Pocari Sweat, has a taste that lives up to its name.

But John McEnroe's unpredictable behaviour on the tennis court kept Dunlop and its advertising agency on their toes, trying to think of ways to translate his outbursts into greater racket sales. After Ben Johnson was stripped of his Olympic gold, no advertiser could hope to be taken seriously in claiming that the secret of his success was the shoes he wore or the tonic he drank.

In future, advertisers will probably prefer to play safe, and to have their products endorsed either by celebrities who are safely dead, or - safer still - by those who never lived. Mario, the New York plumber loved by video-game addicts all over the world, may be duller than today's capricious megastars. But he will surely be safer.