AYRTON SENNA set a new standard in Formula One in 1993 when he agreed a $1 million-a-race deal with McLaren. More than a decade on, the Brazilian is still one of the most sought-after properties in world sport. He is a collector’s item and is generating more money than when he was alive.

Senna always appreciated his earning potential. “I have been in the sport business for 27 years and he was one of the two most intelligent athletes I have ever met,” Julian Jakobi, his agent, said. (He won’t reveal the other.) “He was earning well in excess of $20 million a year, which for that time was big money.”

The Senna industry today is closely regulated and growing every year. “Anything to do with Senna, of some class, sells,” J. P. Boutros, owner of Autosport.net, a dealer in Formula One race-used memorabilia and a Senna expert, said. There are T-shirts, model cars, Montegrappa pens, TAG Heuer watches, Cavaro bicycles, Bell helmets and Ducati motorcycles. Demand for the Senna brand — Driven to Perfection — is high. The limited-edition Ducatis (750 in total) costing $20,000 each sold out. Sid Mosca, who painted Senna’s racing helmets, sells about 180 replicas a year at $800 (about £440) apiece. Bell’s special-edition helmets cost up to $4,000.

There is a big difference between Senna and other sporting greats whose names spin the commercial wheel long after they have been lost to their fans. First, the Senna brand has been so carefully managed that there is little or no black market to speak of. This is partly because Senna fans are discerning and partly because Bernie Ecclestone, the Formula One promoter, comes down hard on knock-off merchants at grands prix.

Secondly, a specific proportion of the money generated on the back of his image is directly accountable to a significant social benefit. At least 5 per cent of the value of licensed products is paid in royalties to the Ayrton Senna Institute, a not-for-profit charity organisation. Extrapolating from the institute’s accounts, Boutros estimates that at least £74 million worth of official Senna merchandise is sold every year. A large source of the institute’s income is Senninha, the cartoon character that the late champion based on himself, and Senninha Baby, a spin-off. More than 350 branded products, from food and toys to books and lunch-boxes, are licensed and all the revenues go to the institute.

The institute also receives about 11 million Brazilian reals (about £2.1 million) a year from its corporate sponsors, which include Audi, Ericsson, Microsoft, Nokia and Banco do Brasil.

The other side of the Senna industry is the Formula One memorabilia market, in which the Brazilian reigns supreme.

Michael Schumacher’s helmets go for about $25,000 (about £14,000) each, whereas original Senna helmets range from $40,000 to $55,000. In 1998, Sotheby’s sold a rare Senna helmet for more than $62,000 (£37,000). Schumacher’s are worth less because of their greater availability — he wears up to three helmets per race weekend, while Senna wore only between six and eight a season.

He was also immortalised by an untimely death. “There is a James Dean phenomenon here,” Boutros said. “Senna had a lot of charisma to start with, but dying in a blaze of glory didn’t hurt.”

There is likely to be a surge of commercial activity around the 10th anniversary of his death. Mosca reports that he is selling 50 replica helmets a month compared with the usual 15. A concert in São Paulo on the eve of what would have been Senna’s 44th birthday attracted a crowd of 25,000.

There are exhibitions, internet campaigns, a book by Norio Koike, the Japanese photographer, charity marathons and a journalism award, all planned to raise awareness of the institute’s work. Viviane, Senna’s sister and president of the institute, would rather not be embarking on the commemorative roadshow that will also include a football match in Italy this week between Formula One drivers, including Schumacher , and Brazil’s 1994 World Cup champions.

Watching Gerhard Berger complete one lap at Imola on Sunday in the Lotus-Renault JPS-1986 that Senna drove in the 1986 season will be too much to bear. But she does plan to stay for the grand prix. Her emotions are too close to the surface, but she is doing it because she hopes to attract more corporate investment to social projects.

There will be profiteers; two unofficial books are about to be published. “There are people that make bad use of the event as well as there are people who can do exactly the contrary — to transform a great tragedy into something good,” Viviane said. “This is out of my control.”

What she can control is of great value: a slice of the future earnings of one of the most marketable men in sports history. The power to preserve an uncorrupted memory of her little brother is priceless.