There is a notice that confronts you in one of the restaurants in the Olympic Village as you totter up to the till with your tray of fast food. It says simply: "We are proud only to accept Visa here." And every time the hackles rise and I am tempted to say to the smiley little waitress: "And I am proud only to offer American Express", just to see what the reaction would be.

Forget faster, higher, stronger and think of the Olympics more in terms of richer, richer, richest. The modern Olympiad is driven not so much by sport as business. Big business. Sponsors rule the athletes they sign, big backers determine what you eat and wear and American television decides when you will watch your favourite event because it suits their schedules.

Of course, we all know that money and sport are now happy bedfellows; just look at wages in the Barclays Premiership. Oh, that was the Barclays Premiership I mentioned. Don't think for a moment that it is an accident when Usain Bolt strips off his golden running shoes for the cameras. Pre-planned by his sponsor? You could suggest it, I couldn't possibly comment.

And how much crowing was there at Nike each of the eight times Michael Phelps stepped up to the podium to receive his gold medals. Phelps was promised $1 million by Speedo, his sponsor, if he achieved the Golden Eight. But the USA Olympic team is sponsored by Nike, and that is what he had to wear on the podium.

What can the Chinese here in Beijing make of it all? Especially, when they discover the only credit card they can use is Visa, the only clothes they can wear come from Adidas, the only food they can eat is a McDonald's - and the Big Brother Olympic authorities will make sure it stays that way for their big bucks sponsors. Only we pay the price.

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Pleased as punch would be one way to describe Yang Yuanqing, for example. He is chairman of Lenovo, China's fast-growing electronics giant. Lenovo is an official Olympic partner and Yang made sure that his company funded Beijing's bid for the Games. His reward? He got to carry the Olympic torch on its way into the capital. But then so did Winfried Vahland, president of Volkswagen in China. Blimey, even Ingrid, his wife, got a turn in the limelight with the torch. And you will have realised by now that these men run companies that run the Olympics. Could it be a case of cash for Olympic honours?

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Perhaps the Olympics is the true embodiment of the spirit of enterprise. At least, it is to some extent in China where they don't miss a trick when it comes to making money, in spite of their recent Communist heritage. The authorities have tried to stamp out the impromptu street stalls that appear on every corner but the traders are not remotely deterred. They even set up on the corner by the main20security gate, selling Olympic badges and knick-knacks - and they found plenty of willing buyers.

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Even the opening ceremony was not immune from a little local enterprise. You will remember Li Ning, flying around the perimeter of the Olympic Stadium to light the Olympic flame that marked the opening the Games. Turns out he was also indulging in a spot of "ambush marketing". Seems investors rushed to snap up a piece of his Hong Kong-listed company, which makes running shoes and sportswear, immediately after his appearance on worldwide television. The share price of his business jumped enough, they tell me, to make him around £15 million.

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Just how much pressure has been on Liu Xiang these past few days? China's biggest hope for gold on the track is a one-man money machine here with sponsors falling over themselves to sign up one of the nation's biggest sports stars.

According to China Daily, the major English language newspaper out here, Liu has 14 personal sponsors, ranging from Nike to Coca-Cola and Cadillac, paying him around £12 million-a-year, which putts him second on the earnings league table of Chinese sports stars only to basketball giant, Yao Ming.

So it was a disaster when Liu pulled up injured in the heats even before he had the chance to defend his Olympic 110 metres hurdles title. The billboards were ready to go, the button about to be pressed on the television=2 0adverts and, suddenly, there was no show for the biggest Chinese name on the track. But these sponsor chaps don't make big money for nothing. Within hours, Nike had changed their print ads to read: "Love sport even when your heart breaks"

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By the way, what do you think? A mass manufacturer of burgers and the world's biggest supplier of fizzy drinks are among what they call tier-one sponsors of the Olympics. So how does that square with the objective of the London 2012 Games, at least, to get kids off junk food to combat obesity?

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Sometimes, you can forget it is all about money, though. I did and it came from some magical moments of celebration with Heather Fell, Britain's silver medallist in the modern pentathlon. This is a kid who will probably never earn huge amounts from sport. In fact, she almost dropped out a couple of years ago after being plagued by injury and her funding from UK Sport was stopped. She moved in with her parents and took three jobs to pay the bills until she could get back into athletics.

When she picked up her medal, that smile probably beamed all the way from Beijing to light up her home town of Tavistock in Devon. But best bit came as she set off for the stadium exit, only to be interrupted by a Chinese fan who wanted his picture taken with the new Olympic siver medallist. "That reminds me," she said. "I must take some pictures. I want=2 0to remember this" She deserves to.