PLATFORM:THE SPORTS business story of the week centres on the marketing value of Lewis Hamilton, the youngest-ever winner of the Formula One drivers' world championship. Hamilton is talented, photogenic and seems well liked, if you don't count his competitors on the grid or the racists who make up a sizeable section of the Spanish and Brazilian motor sport communities.

It's unsurprising that his victory in São Paulo led to much analysis as to his future earning power, with a few papers talking of him countering the dire financial outlook to become Europe's first $1 billion sportsman, or "England's Tiger Woods".

This type of thing is a regular staple of the sport and business pages and is usually horribly inaccurate. Sponsorship stories are a problem for the papers because they feel incomplete without a figure, but getting the real numbers is difficult, so journalists often just take the lines they are fed from PRs working either for the agent or sponsor.

A big number is useful for those on both sides of the deal: the brand gets an eye-catching headline and comes across like a heavy hitter; an inflated fee helps the star's agent, who can use it as a baseline from which to start negotiations with other prospective sponsors. The degree of inaccuracy in this area of reporting is huge, according to one contact within the sponsor research industry, who once told me that the figures in the press are usually about 75 per cent or more above the real numbers.

But other factors combine to make the guessing of Hamilton's future earnings more complex than the billion-dollar-man headlines suggest.

First, what has he got left to sell? McLaren has about 25 of its own sponsors, all or most of whom will have written in to their contracts some access to Hamilton. This could range from permission to use him in their advertising to smaller but equally time-consuming things such as meet and greets in the Paddock Club or at McLaren's headquarters.

So, when selecting which companies he can associate with, Hamilton's advisers will need to steer clear of any brand that conflicts with McLaren's stable of commercial partners, such as Vodafone, Santander, Hugo Boss, Hilton Hotels and Johnny Walker, the Diageo-owned whiskey brand.

Finding a way through the potential conflicts between the individual athlete and a team or national association is one for the lawyers, but the issue raises questions as to who actually owns the Lewis Hamilton brand, and who has invested most in building its commercial value.

Is it Lewis himself, or McLaren, which has invested millions in training and marketing him and giving him the ride in a competitive car, which itself costs hundreds of millions of euro to develop? Or is it Formula One, in the person of Bernie Ecclestone, who owns the means by which Hamilton, and McLaren, have become famous and rich.

Then there's the question of how an association with Lewis Hamilton is beneficial to a sponsor. This, too, is more difficult than it seems on the surface. The company is paying to associate its image with that of the athlete and is hoping that his or her star quality will rub off on the brand. The evidence that this works is mixed at best.

The problem is that the matching of sponsor to athlete is more art than science, done on a hunch rather than through effective research, and the presence of the 24/7 celebrity-obsessed media makes it harder to make that link seem plausible.

Occasionally, buying up an athlete can be cost-effective. Sportswear company Puma was deemed to have had a good Olympics due to its sponsorship of Usain Bolt, the double gold medallist sprinter who paraded around the Birds Nest stadium in Beijing waving his gold Puma shoes above his head. The price of a pre-Beijing Usain Bolt was a small fraction of the IOC official partnership deal signed by Adidas, Puma's arch-rivals.

Personally I have no problem with top athletes like Bolt and Hamilton filling their boots. If someone's willing to pay then that's what they're worth. But there is a bigger issue here: we the viewing public are being short-changed.

The cult of the "Brand Ambassador" is steadily smoothing out the rough edges of successful young sportspeople. They see the really big contracts going to those athletes who are deemed a safe pair of hands and who are less likely to jeopardise a multimillion-euro advertising campaign by being caught up in a tabloid kiss-and-tell or being put on a drugs charge. Tiger Woods, Roger Federer and yes, Lewis Hamilton, is each talented and good-looking. But, in public at least, they are also very, very boring.