Things to do in Johannesburg today: pose for photos beside the six-metre-high bronze statue of Nelson Mandela in Nelson Mandela Square. Take in a show at the Mandela theatre, cross the Nelson Mandela bridge, behold the Nelson Mandela Day banner in Newtown and head to the Apartheid museum's Mandela exhibition. Finish up in Soweto at Mandela House, a museum in the anti-apartheid hero's former home.

In certain parts of Africa this cult of personality would seem downright sinister. But South Africa's first black president has the blessing of democrats around the world. His 91st birthday on Saturday -- declared the first Mandela Day -- is being celebrated in his homeland and beyond.

The events will highlight what has in effect become a one-man industry. Streets, squares, schools and a World Cup stadium are named after Mandela. His image looks out from books, posters and newspaper front pages. Later this year he will be played by Morgan Freeman in a Hollywood film. Four organisations in South Africa bear his name and seek to further his legacy.

They are also fiercely protective of the lucrative Mandela brand. A request last year to advertise Viagra with the slogan "We are 10 years old, Mandela is 90" was politely turned down, and those who seek to exploit the name without permission can expect swift legal retribution.

But from Russian dolls and car licence plates to fridge magnets and salt and pepper shakers, there is no shortage of unauthorised attempts to cash in on his image. Mandela himself is now tired of being exploited. "He's sick of seeing his own face everywhere," a friend said on Friday. "I've watched him looking at all these representations of himself and I can tell he's had enough."

South Africa's official marketing website pronounces confidently: "It's the birthday of the world's favourite person." Such is his global appeal that New York is hosting a fundraising concert at Radio City Music Hall with performances by Stevie Wonder, Aretha Franklin and France's first lady, Carla Bruni-Sarkozy, and guests including Whoopi Goldberg, Forest Whitaker, Morgan Freeman, Matt Damon and Susan Sarandon.

The Nelson Mandela Foundation has called on the public to devote 67 minutes to worthwhile causes, symbolic of Mandela's 67-year career in public service. A spokesperson said the man himself would be keeping a low profile: "It is a quiet day for him -- spending with friends, family and comrades."

Unlike others commemorated in bronze and stone, Mandela is alive to witness the construction of his legend. But he feels a line should be drawn. He was once quoted as saying: "You can Kennedy-ise my name, but not Disney-ise it."

Asked if there was a danger of overkill, Verne Harris, programme manager of the foundation's Nelson Mandela Centre of Memory and Dialogue, said: "Totally. There's a fatigue on the part of Madiba and of stakeholders in his legacy. Any reasonable view would say that we've saturated this now, how many more Mandela Avenues can we have? Only yesterday I got a message saying that Nablus in Palestine has given him the freedom of the city, named a street after him and asked him to send a message. That puts us in very difficult position."

The foundation's intellectual property manager receives 10 requests a week to use Mandela's image. It is aware of 450 unofficial websites registered with variations on his name, as well as dozens of unlicensed trinkets for sale on eBay and in townships. "Madiba has told us that he's not comfortable with the commercial use of his name and image," Harris said. "We're looking for examples of gross exploitation, but there are grey areas. The number of court cases has been minimal. Usually a legal letter does the trick."

The Mandela legacy has also provoked some unseemly controversies. His grandson, Mandla Mandela, is considering suing newspapers over reports that he tried to sell the TV rights to Mandela's funeral for over R3-million.

Mandla has also been accused of trying to evict a cousin from her home to turn it into a Mandela tourist attraction.

Commentators believe it is no coincidence Mandela Day should be launched under the presidency of Jacob Zuma, who will spend his 67 minutes on Saturday meeting elderly people. Zuma is said to be far more comfortable than former president Thabo Mbeki was in Mandela's shadow.

A source close to the ANC said: "Mandela and Mbeki never hit it off. During the Mbeki presidency there were even some attempts to airbrush Mandela out. But people in the Zuma government are saying they want to go back to the values of Nelson Mandela."

Some warn that the idolatry of any man, even Mandela, is best avoided. Jeremy Gordin, Zuma's biographer, said: "The whole Saint Mandela thing has obscured the history of the ANC and the relationships between people. He's not a saint, he's a human being; he's a wonderful man, but he made mistakes." - guardian.co.uk