As Mandela reaches 91, who's celebrating?

Carla Bruni has been persuaded to take to the stage for the first time since becoming France's First Lady and will be out in force tonight with Aretha Franklin, Alicia Keys and a host of other stars to fete our planet's last living legend.

But even as Stevie Wonder sings Happy Birthday to the South African freedom revolutionary-turned icon of humility, Nelson Rolihlahla Mandela will be safely tucked up in bed at his house in Houghton, Johannesburg.

"He is 91! He always has an early night, like anyone his age," said a spokeswoman for Mr Mandela's office. "The birthday will be the same as every year – strictly for family and comrades. He will stay home all day."

The New York concert at Radio City Music Hall marks the high point of Mandela Day, declared by 46664 – the charity named after his Robben Island prisoner number – and the Nelson Mandela Foundation to rally ordinary people all over the world to do voluntary work. In New York, the concept has taken off to such an extent that today marks the end of Mandela Volunteer Week.

But in South Africa, the story is different. "Mandela Day? Do you mean his birthday? Is there an event this year?" asked 19-year-old Andile Ngcolomba, a student in Khayelitsha township near Cape Town. "I haven't heard of any volunteering initiatives. We're on summer break so nothing has been arranged. Besides, I am not sure Mandela did so much for us."

This is the problem with Mr Mandela – featured on coasters and clocks all over the world – and whose flesh all politicians feel a compulsion to press as soon as they are elected. He has outgrown the status of a mortal. In the process, he has been taken away from South Africa. He has become so big that his own nation – barring an angry schoolboy in Khayelitsha and a small number of intellectuals – fears to scrutinise his legacy.

The first words he pronounced publicly on his release from 27 years of apartheid captivity on 11 February 1991 never really came to pass: "I stand here not as a prophet but as a humble servant of you, the people." Later in the 1990s, even as the Aids epidemic was spreading in the country of which Mr Mandela was president, the South African people were left watching their hero offer photo opportunities to the Spice Girls.

Mr Mandela – also known by his clan name Madiba – personifies the defeat of apartheid. He ranks as an icon with Gandhi and Martin Luther King and has accumulated the mystique of legend in his own lifetime. Hardly a city in the world doesn't have a Mandela Street, or Square. His charisma continues to floor whole assemblies. An appearance by the frail moral colossus on the campaign trail helped give Jacob Zuma's presidential campaign a shot in the arm.

Only last weekend, his surprise attendance at the Seventh Nelson Mandela Memorial Lecture – delivered in Johannesburg by microcredit pioneer Professor Muhammad Yunus – entranced the audience. The magic is inescapable: When you see Mr Mandela in a crowd, it is as though his face emits rays of sunlight.

There are rumours (but no evidence) that his health is failing and that his mental faculties have waned. This year, he has not made live public speeches; they have been pre-recorded and played in his presence. It has been several years since the press corps was called to his Houghton lawn for a Friday afternoon health briefing. Fridays, after the closure of the markets, have always been chosen for Mandela health news, so as to protect the national currency, the rand, from a potential sudden collapse. Either his condition is stable or the secrecy has been increased.

Mandela Day seeks to celebrate the 67 years he is reckoned to have dedicated to political service, by asking volunteers to dedicate 67 minutes of their time to a good cause today. In South Africa, President Zuma will spend his 67 minutes with a group of elderly citizens. The ANC has deployed ministers, members and youth leaders to paint a police station, visit a hospice, plant trees and give clothes to orphans. The highlight is a free concert featuring local pop stars, organised by the ANC in central Johannesburg.

But the collectivist party political flavour of Mandela Day in South Africa distances it from the stated intention of the initiative – "celebrating the idea that each individual has the ability to make an imprint". It also leaves out the majority of South Africans of all races, many of whom are struggling to survive in poor accommodation amid high levels of crime, and are victims of corruption by local officials. Trade unions claim more than 20,000 workers have been retrenched in the car industry since last autumn. Up to 50,000 jobs are at risk in the mines. The 70,000 construction employees whose strike last week halted work on the 2010 World Cup stadiums was centred on pay rises for workers earning as little as 13 rand (97p) an hour.

Cape Town waitress Germaine Roberts, 35, who is white, said: "You won't see many ordinary white South Africans doing much. Only rich whites will do stuff because they feel guilty. I wish Mandela had never been president. He made a lot of empty promises. Here in South Africa, we see the result, and it's a lot of poverty."

One of South Africa's most outspoken newspaper columnists is Andile Mngxitama who appears in the Sowetan newspaper. "I do not know anyone doing anything for Mandela Day, and I certainly am not. Mandela has been turned into a pop star but this country is sitting on a social time bomb," he said yesterday. "The majority of people are living outside his dream. Because he is rated second only to God, and it is too weighty for anyone to ask questions about God, we are not scrutinising what we got and what we gave away when Mandela negotiated our transition from apartheid.

"One of the things he negotiated was this awful national anthem we sing, which includes a verse from 'Die Stem', the anthem of the apartheid government. It is as though you got Jews to sing a Nazi verse. What are we doing to young black children by making them sing this? Indeed, what are we doing to white children by telling them this song is part of their heritage?"

Yet since his release from captivity, Mr Mandela has been about music. His close association with pop stars has made this a fact. Today's concerts in New York and Johannesburg mark the further crowning of a celebrity icon. It is a shame, admits Sello Hatang, head of information at his foundation, who insists Mandela Day is not about pop. It is about humble service and, in South Africa, its aim is to empower people to take hold of their destinies. "Madiba did not have hundreds of thousands of rands but he changed this nation for ever."