JACOB ZUMA scored a victory last week that was so stunning, so overwhelming, so momentous that for a brief moment his own supporters could barely take it in.

Then the singing, dancing and tears of joy that had erupted among his followers spread like bushfire from the conference at the University of Limpopo, Polokwane, to the Zulu heart-land in Zuma’s native KwaZulu-Natal at the news that he had trounced President Thabo Mbeki for the leadership of the ruling African National Congress (ANC).

Elsewhere there was shock: no other African state has seen such a frontal rejection of authority. There was disgust among some voters, who will never trust Zuma after allegations against him of corruption and rape. Others, including wealthy whites and black middle-class supporters of Mbeki, felt a sense of panic.

“I’ve always said that the one thing that could drive me to emigrate would be a Zuma victory,” said Dr Michael Jordan, a paediatrician who is married with two children. “Now the whole family’s on the beach for Christmas and I’m having to think those thoughts.”

What nobody doubted was that it was the biggest turning point since the country embraced democracy in 1994.

On the radio phone-in programmes, many black callers celebrated the arrival of “working-class leadership” and the coming socialist revolution, although such calls were frequently punctuated by whites ringing in to say that Zuma’s victory was the final straw and they were considering emigration.

It hardly helps that Mbeki, in the run-up to the conference, let it be known he believed a Zuma victory would reduce South Africa to “a neo-colonial basket case” or “just another African kleptocracy”.

Not only did Zuma defeat Mbeki by a better than 60-40 margin, but all six executive positions in the ANC went to Zuma’s team by similar margins and the same occurred in elections to the party’s 80-strong national executive (NEC).

Anyone who had spoken against Zuma was flung out, as was anyone associated with Mbeki. In all, 15 cabinet ministers, 10 deputy ministers, 10 MPs and all but one of the provincial premiers lost their NEC posts. In effect the party had delivered a massive vote of no confidence not only in Mbeki but also in executive authority throughout the country.

If Mbeki had not been so blithely overconfident he would have realised long ago that once Zuma rounded up the support of the party’s biggest pressure group, the 1.9m-strong Congress of South African Trade Unions (Cosatu), and its largest ethnic group, the Zulus, he was bound to be a formidable opponent.

Mbeki, who had already decided to run again for ANC president, seemed to be in a state of denial. No wonder Zuma, in his first speech as party president, spoke of how the leadership had ceased to listen to the people.

Despite the continuing economic boom the poor have not benefited. Last month the South African Institute of Race Relations released data showing that thanks to growing inequality, the number of people living on less than $1 a day had more than doubled between 1996 and 2005. Mbeki’s response was to denounce the data as lies.

Mbeki, it had become clear, speaks for the new black middle class who have never had it so good. At Polokwane his ministers and supporters parked their 4x4s, Mercedes and BMWs where the Zuma supporters could not fail to see them.

At the end of each day they would roar off to luxurious hotels while the Zuma-ites plodded back to their spartan rooms in the down-at-heel university residences.

By the end Joel Netshitenzhe, Mbeki’s spokesman, was reduced to pleading that “the well-off must be convinced that they have a responsibility towards the less advantaged” and that they should avoid “conspicuous consumption and ostentation”. It was simply too late for that.

There is no doubting the fury of the black elite with Mbeki.

Educated Africans from Archbishop Desmond Tutu down deplore the fact that the choice came down to Mbeki or Zuma. They believe Zuma is tainted by corruption charges and his rape trial and that he is a barely literate man without the skills required to govern a complex society such as South Africa’s.

“It’s entirely Mbeki’s fault that we’ve got Zuma as president,” said a black professor. “By insisting on standing again and making it impossible for anyone else to run, he narrowed the choice quite artificially.”

Mondli Makhanya, editor of the Johannesburg Sunday Times, agreed: “South Africa deserved a better choice. I was hoping desperately for a third candidate to emerge.”

Zuma, Mbeki and the ANC elders have decided Mbeki must serve out his term until May 2009 while Zuma holds all power in the party.

This is the “two centres of power” scenario that the ANC had earlier been eager to avoid.

The new structure is inherently unstable.

Zuma will have his own inner cabinet of advisers in Luthuli House (the ANC headquarters) while Mbeki’s cabinet will look like lame ducks, having just had the ruling party vote no confidence in it.

The markets are bound to test these new arrangements hard and both the rand and the stock market look vulnerable. While Zuma is keen to disavow any appetite for radical change, business is uneasily eyeing his need to pay off his Communist party and union backers.

The Communists have demanded the nationalisation of Sasol, the giant energy and mining conglomerate, and the South African division of Mittal Steel, the continent’s largest steel producer. They also want an expan-sionary economic policy, with the government taking political control of interest rates.

This alone creates uncertainty. In addition, government prosecutors announced on the eve of the conference that they had further evidence with which to put Zuma on trial for corruption, fraud and tax evasion, raising the possibility that he could soon find himself in court or even in prison. The unions have declared that any further charges brought against Zuma must be regarded as being “trumped up” and threatened a general strike.

Zuma’s supporters believe the case against him is Mbeki’s doing and that he has shamelessly abused state institutions for partisan purposes. Any further move to prosecute Zuma might well lead to a parliamentary vote of no confidence in Mbeki – the ANC has the necessary two-thirds majority.

This would bring the two centres of power crashing down and lead to an early election. Yet even Mbeki’s supporters wonder if he can desist manipulation. As Mark Gevisser, his biographer, says, Mbeki views all politics as conspiracy – his own or someone else’s.

Mbeki has almost no family life and, in effect, the ANC has been his life. From the time he came to Britain as a Sussex University student he was seen as the ANC crown prince, destined for greatness. Now this lifelong dream has ended in defeat and public humiliation.

There is no doubt about the depth of antiMbeki feeling. One delegate at Polokwane, seen to be packing up to go even before Zuma’s closing speech, explained: “We came here to vote Mbeki out, not to vote Zuma in.”

A last-minute decision by the Inkatha leader, Chief Mango-suthu Buthelezi, to support Mbeki was based on the realisation that Zuma will now steal Zulu supporters from all other parties, so great is the enthusiasm to see another Zulu leader of the ANC.

Zuma has spoken movingly of his desire to help rural women, the poorest of the poor, and already his tribal members in Zululand are making it plain that they expect to see immediate benefits from his elevation.

Even at Polokwane it was clear that there could have been violence if Zuma’s Zulu supporters felt that vote-rigging had robbed them of victory. For them it has already become a Zulu victory. Anyone who wishes to snatch that away will have to be prepared to fight.

Video: Jacob Zuma announced as new ANC president

Video: South African reactions to Zuma's victory

Video: Jacob Zuma on African diaspora skills

Times Recommends

• ‘Thousands of Tamils dying’ in Sri Lanka camp
• Jackson 'rebuilt his nose before he died'
• Tehran: militiamen attack protesters