'We have now arrived at the moment when we go back to work," said Thabo Mbeki at the conclusion of his victory speech at Gallagher Estate, in Midrand, on Thursday afternoon. Almost wilfully out of key with the jubilant supporters filling the hall, it was his purest statement yet of anti-populism: there was no wife at his side, no rah-rah, no triumphalism - just a clear recapitulation of his policies and a sober, authoritative confidence.

Nelson Mandela was not there and was referred to only in passing by Mbeki along with "the hundreds of leaders and activists" who needed to be thanked; an indication that the real transfer of power from Mandela to Mbeki had already taken place 18 months previously - at the party's December 1997 conference in Mafikeng.

"Madiba," Mbeki had said then as he stepped up to the podium, "members of the press have been asking me how it feels to step into your shoes. I've been saying I would never be seen dead in such shoes. You wear such ugly shoes!"

At that moment of gravity - a moment on which Mbeki's entire career had been focused - he was betrayed, momentarily, by the schoolboy in him, by the awkward braggadocio of someone whose performance had been measured, perpetually, against the stature of a "father" even before he had been given a chance to prove himself.

He then switched to Xhosa: "If you don't see tears in our eyes, Madiba, it does not mean we are happy . . . We will always seek to ask you for help, even if it is for you to carry my briefcase so that I can walk around with my hands in my pockets."

Metaphorically and literally, Thabo Mbeki has spent his adult life carrying older men's briefcases. He did it for ANC secretary-general Duma Nokwe in the'60s, for ANC president Oliver Tambo throughout the years of exile, for Nelson Mandela over the past five years. Now that he no longer has his hands full with other people's bags, he is learning how to use them - to embrace, to feel, to applaud, even to slap. He will sling an arm, with studied insouciance, around a child's shoulders during a campaign walkabout; he will slam a fist into the air at a rally, he will point a finger at adversaries.

But like many clever, capable people who have spent most of their professional lives in the background, in the shadows of their bosses, Mbeki has learnt the art of wielding power without showing it, for he has had responsibility without authority. This might be one of the reasons he has developed a reputation for being "manipulative" and "devious".

Indeed, at Mafikeng in December 1997, what seemed to put the new president of the ANC on edge was the fact that Nelson Mandela had welcomed him to the presidency with a sermon: "One of the temptations of a leader who has been elected unopposed," the old man said, "is that he may use his powerful position to settle scores with his detractors, to marginalise them and in some cases get rid of them, and to surround himself with yes-men and women . . . The leader must keep the forces together, but you can't do that unless you allow dissent . . . People should be able to criticise the leader without fear or favour. Only in that case are you likely to keep your colleagues together."

The speech was vintage Mandela: in assuring the delegates that "fortunately, I know our president understands these issues [and] he is not the kind of man to sideline anyone", he was simultaneously calming fears about his successor and warning him, in the most public way possible, that these fears existed and needed to be addressed.

The roots of these fears are to be found in the extremely complex world of exile politics; a world into which Thabo Mbeki was thrust and which he ultimately conquered. It was in exile that Mbeki found his particular path to leadership; in exile that he developed the key relationships that were to propel his ascendancy in the liberation movement - with his mentor, Oliver "OR" Tambo, and with the SA Communist Party. Balanced between the pragmatism of the former and the ideology of the latter, he developed a leadership style - and an approach to liberation - that he deploys to this day; one that played a major role in bringing reform to the ANC (and, ultimately, through negotiations, peace to South Africa), but that has also caused political difficulties for him so serious that they almost cost him the deputy presidency in 1994.

There is a story told of how the young Thabo Mbeki caught Oliver Tambo's eye. In London in the '60s, after Tambo gave a group of youngsters an assignment, Mbeki suggested they all go to a pub. A few hours later, at closing time, the others all rolled out blind drunk, but Mbeki - perhaps because of abstemiousness, perhaps because of his legendary capacity to hold his liquor - went home and worked through the night. In the morning, only he had done the homework. The ANC president realised both his brilliance and his vulnerability, and took him into his protection.

The story is unverifiable and perhaps apocryphal, but it points to the way many of his peers felt about the way he deployed his cleverness to outwit and outperform them.

While Thabo Mbeki had always been earmarked for senior leadership, his true apprenticeship for the ANC presidency began in 1978, when he was 36. He had worked on the front lines, in Swaziland and Botswana, for two years - where his major contribution was to bring black consciousness leaders into the ANC and to re-establish the reputation of the ANC in the minds of black South Africans - and had been sent to Nigeria as the ANC's representative for another two.

Now Oliver Tambo brought him back to Lusaka and appointed him his political secretary. He was already on both the SACP Central Committee and the ANC's NEC, but this appointment vaulted him into a position of influence far beyond his place in the hierarchy, for he became Tambo's proxy; the de facto deputy president of the ANC.

He was known, in some quarters, as "the national interferer", but, says one of his contemporaries, "you might have resented him for interfering, but you couldn't do without him, for he was clever, efficient, and he had a direct line to the chief. If you wanted to talk to Tambo, you had to talk to Thabo."

Tambo was already Mbeki's mentor and guide, and Adelaide Tambo recalls how he "became the brother of my children - in exile, he was like my first-born". But perhaps the reason the Tambo-Mbeki partnership was so effective was that neither ever allowed it to cross the boundary into familial intensity, into the father-son territory of tensions and rivalries - ground that Mbeki's relationship with his own father, Govan Mbeki, appears to have occupied.

And Mbeki has a very different personality to Tambo: the former is always emotionally controlled, and speaks in reasoned, measured tones, while the latter had an excitable streak and tended to express himself through staccato outbursts. Joe Nhlanhla, the Deputy Minister of Intelligence, remembers watching the two of them, both highly musical, listening to records together. "Thabo had this way of sitting back with his eyes closed and absorbing it, being cool, while OR would move his hands about, as if he wanted to conduct the orchestra himself."

Mbeki had begun working for Tambo as a speechwriter in the '60s; in ghostwriting, he found the perfect vehicle for his particular combination of diffidence and intellect. He could apply himself, fully, to drafting ideas for Tambo to articulate that he had neither the authority nor the volubility to say himself.

The stories of the exacting, pedantic Tambo's speech-drafting sessions have an almost novelistic texture to them. To prepare for an address, he would get several of the young intellectuals in the movement to draft speeches for him, keeping them up all night for days on end, sending an entire draft back to be retyped because of a split infinitive or a superfluous comma. He would often require them all to draft the same speech, and would then choose the best - invariably Mbeki's.

After 1978, Mbeki's role as the liberation movement's word- smith was formalised in his new appointment as political secre- tary. The obvious place for heroic advancement in a liberation movement is the army - look at Chris Hani, at Che Guevara, at Samora Machel. But Mbeki seemed to understand that the confluence of his character - the intellectual, the anti-hero - and the rehabilitation of the ANC (which was shambolic in the late '70s) lay somewhere else.

And so, one of his first actions was to take control of the Department of Information and Propaganda (DIP), changing the "P" to "Publicity" and using it to expose the liberation movement to the light of day. He defined his role "as giving information about the ANC to whomsoever required it". This included rebuilding the ANC's image inside South Africa via propaganda media like Radio Freedom, granting interviews to journalists and, later, receiving the cavalcades of white South Africans who were to make the pilgrimage to Lusaka.

Mbeki's genius in the '80s was not only that he seduced white South Africans, particularly Afrikaners, out of the arms of the apartheid government, but that he seduced the West into the arms of the liberation movement. Using his pipe and his intellect (not to mention his whisky decanter) to maximum effect, he exuded bonhomie and reason in equal measure.

Paradoxically, though, his very success at this role was to create enduring problems for him within the ANC; problems which, as we shall see, culminated in the political difficulties he experienced in the early '90s on his return to South Africa.

Mbeki was often scorned by MK cadres for having had a cushy life flitting around the world's capitals and for never having experienced the hardships of life in the camps. Indeed, in his mutinous (according to the ANC) 1969 memorandum to the leadership, Chris Hani railed against the fact that "virtually all the sons of the leaders" had "been sent to European universities", "a sign that these people are being groomed for leadership positions" after MK cadres like himself "have overthrown the fascists".

The "softie" taunt was to haunt Mbeki, but was not entirely accurate: he received a year-long, high-grade military training in the Soviet Union in 1970, and, for the two years he lived in Swaziland, he acted as a military commander (Jacob Zuma, who went into exile to join him in Swaziland, recalls how "Thabo taught me how to use a gun").

His life in Swaziland was dangerous: after the kidnapping of two comrades by South African forces, he and Zuma spent a month in Swazi "protective custody" before being deported to Mozambique in mid-1976.

But Mbeki nonetheless did not have an easy time countering the stigma. One of his first actions when back in Lusaka in 1978 was to authorise a CBS crew to interview senior ANC officials and to film in the ANC's Angolan camps. The result, a 1978 programme entitled The Battle for South Africa, was a major publicity coup for the movement in the US, but caused indignation in the ANC community: Mbeki discovered, a year later, "that our own intelligence had classified me as a CIA agent".

The fact that Thabo Mbeki was once under suspicion by the intelligence services of his own organisation says much both about how paranoid and fearful those times were and about how contentious Mbeki's own history within the ANC has been.

Those close to him say that the "CIA" or "sellout" tag stemmed in part from resentment; he was perceived to be a youngster with too much power, overstepping those older and more senior than him. The tag, which was to follow Mbeki all the way through into the '90s, was often deployed by those who resented his meteoric ascendancy, or what they perceived to be a "pragmatism" short on principle.

He was by no means isolated, though: he remained Tambo's right-hand man and maintained his positions in the senior leadership of the SACP. Elders like Joe Modise and Alfred Nzo remained loyal to him, and he developed around him a powerful group of followers who were to form the backbone of his "talks" teams in the late '80s: Jacob Zuma, Joe Nhlanhla, Aziz Pahad, Penuell Maduna. He mentored his own protégé - Joel Netshitenzhe - in much the way Tambo had developed him. Most of all, his strategic mind and intellectual capacity made him indispensable even to those who mistrusted him.

To understand the complex position that Thabo Mbeki held within the ANC's exile structures, one has to look at how he rose along two parallel routes: the first was at Oliver Tambo's side, and the second was in the SACP - which was not only the intellectual vanguard of the movement but in control of the army and, via the Eastern Bloc, its purse strings too.

It remains a nigh-impossible task to track this second route. Mbeki has never spoken publicly about his SACP leadership before; indeed, the authorised "biographical sketch" to his recently published anthology of speeches does not even mention it. In this area, Cold War winds continue to blow, and the pacts of secrecy cemented during the struggle hold even now: comrades still will not talk about their organisation and its leadership. This is not only because of the way the apartheid regime used the SACP against the ANC, but also because it was agreed, in 1990, that each SACP member would make his or her own decision as to whether to go public.

However, this continues to sow confusion and dissent. Some SACP members maintain that Thabo Mbeki remains a communist and is simply "underground"; others resent him deeply for having, in their eyes, used the party when it suited him and dumped it expediently when it did not. Now, to his credit, Mbeki has agreed to go public for the first time about his position and role in the SACP. Old habits die hard, though, and he was not able to confirm when he was elected to the Central Committee and the Politburo - the SACP's two highest organs.

But, in a remarkably frank interview, he did confirm that he was recruited to the SACP in 1962 and that he was on both the Central Committee and the Politburo until the unbanning in 1990, when he made the decision to let his membership lapse because "with the unbanning, the question arises, can you adequately represent the position and interests of the ANC with this requirement that you [be] equally active in this separate independent party programme of the SACP? . . . In our particular instance we were too senior in the party just to say, 'I'm a member', and not do any party work . . . The principal challenges of the time had to be met by the ANC . . . In those circumstances, choices had to be made."

Mbeki denies that he had long drifted from the SACP, and that the unbanning just gave him a convenient excuse to sever his ties. Others note that someone with as open a mind as his would have chafed against the orthodoxies imposed by the party and would have found it difficult working under the leadership of Joe Slovo after his election as general secretary in 1986.

Under the wing of Slovo and of Yusuf Dadoo, Mbeki was as much the SACP's crown prince in the '60s as he was the ANC's.

While studying at the Lenin International School in Moscow in 1970, he was brought secretly to an extended SACP Central Committee meeting that was being held in Volynskoye, outside the city, coincidentally in a dacha that used to be Joseph Stalin's summer home. Here, the decision was made to increase the number of Africans and young people on the Central Committee, and both Mbeki and Chris Hani, in their late 20s, were elected.

And so, five years before he was to be elected to the ANC NEC, Thabo Mbeki was a leader of the SACP. When, in 1977, the party formed its first Politburo (its most secret, highest organ), Mbeki was appointed as the youngest of the original five.

He was dropped from the Politburo in the early '80s - ostensibly because of "non-attendance" - but was reappointed shortly thereafter, and, at the very last SACP congress before the unbanning, in Cuba in April 1989, which he also chaired, he was elected first in the vote for the Central Committee.

But despite his senior position in the SACP, he was frequently at odds with its leaders, particularly Chris Hani and Joe Slovo. Hani and Mbeki - schoolmates at Lovedale and exact contemporaries - have been described, by a close friend of both, as "unwilling participants in a rivalry neither could avoid".

Slovo, unlike Hani, was Mbeki's intellectual equal, and even though Slovo was initially something of a mentor to the young Mbeki, their relationship became fraught with tension and difficulty. The differences were ideological to a point - disagreements, for example, over what the balance should be between armed struggle (which Slovo supported) and mass mobilisation (which Mbeki, along with people like Mac Maharaj, advocated).

Many in the movement say that Slovo could not tolerate his position as senior strategist being challenged by Mbeki; others maintain that Slovo was appalled by Mbeki's expedient use of the SACP and, as time went on, his willingness to compromise towards the end of a negotiated settlement.

Their first major clash came in 1979, during the drafting of "The Green Book", an important policy document that shifted the ANC's focus towards the notion of mass mobilisation via "armed propaganda". This was the time of Frelimo's victory in Mozambique and of the MPLA's victory in Angola, and within this context, Slovo had managed to convince Oliver Tambo - who was not a member of the SACP- that the ANC should cease to be a "national liberation movement" and should become, like Frelimo and MPLA, a "Marxist-Leninist movement".

Mbeki refused to accept this, arguing, he recalls, "that it was wrong, the notion that the ANC was a party of socialism. I said, 'well, if that is the case, then what is the SACP doing? You might as well dissolve it.' " The ANC, he said, had to remain a "broad church" that appealed to all sectors of the population, and "National Liberation" had to remain the objective.

He only won out by enlisting the support of Moses Mabidha, the SACP general secretary (and thus Slovo's senior), who reminded Slovo that his position was not an SACP one.

Six years later, Slovo and Mbeki clashed again, at the ANC's major conference in Kabwe, Zambia, where Slovo rejected the "Strategy and Tactics" document Mbeki had prepared. Ronnie Kasrils, who chaired the Strategy and Tactics Commission, recalls that "Slovo dismissed it out of hand as 'the same old Lenin School formula' and demanded that we find fresher formulations". Although he supported Slovo at the time, Kasrils feels now that the master strategist was displaying his major weakness: "He could not abide rivalry. I greatly respected Joe Slovo and was close to him personally. But it wasn't easy to oppose him, and he did not easily accept that his mantle should be passed on to others."

Whatever its roots, the rivalry between Slovo and Mbeki had profound political implications: as we shall see, Slovo was to become one of the most vocal critics of Mbeki's approach to negotiations and was one of the key people behind the replacement of Mbeki, as the ANC's head of negotiations, with Cyril Ramaphosa.

Slovo and Mac Maharaj - also a critic of Mbeki - were perhaps the returned exile leaders to whom Nelson Mandela listened most; the ANC president's thoughts about Mbeki's role in the '90s were - at first - influenced by them. In 1994 Mbeki's proposal to give Slovo the junior portfolio of Minister of Science and Technology was overridden by Mandela. Up to Slovo's death in 1996, the two worked uneasily together in Mandela's Cabinet.

Mbeki makes a point about leadership by recounting a discussion he and Slovo had after the latter had been elected general secretary of the SACP. "I said to him, 'Watch how OR handles himself at meetings, how he rarely speaks at the beginning of a discussion. You handle yourself differently. You want to speak early in the debate. The consequence is that, having stated your view, you feel obliged to intervene and defend it [even if it has been proven incorrect].'" Slovo, Mbeki says, would put a "product" on the table and thus feel "an obligation to market it".

Mbeki assiduously follows the Tambo approach, which, he says, "allows everybody to say whatever they think without feeling that they are following a line because the president has spoken. It makes people feel more relaxed, and then, once you propose moving in a certain direction, everybody moves with you, without pressure, because they all feel like they've contributed to the idea . . . You are able to move people without banging on the table."

Mbeki's way, says one of his close associates, "is to absorb, take everything in, and then make a decision, as a chief does in a kgotla. Always a compromise, no winners or losers. Everybody recognises everybody else's interests." Mbeki's idea of a good time has always been the Glenfiddich kgotla: plonk a bottle in the middle of the table and spend hours listening to people talk, absorbing their thinking.

But an approach that is ostensibly designed to empower people can have the opposite effect: if you never know what the "chief" is thinking, you are often scared to advance a position for fear it will be shot down and put you out of favour. When his comrades say that Thabo Mbeki does not tolerate dissent, what they often seem to mean is that they don't know what he thinks, and that they fear he will not like their ideas (he does not suffer fools), so they refrain from proffering them. The fact that he withholds opinions and emotions - and that he then dispenses them sparingly - may well be a function of his character, but it is also a powerful way of wielding control.

Frene Ginwala, who worked directly for Oliver Tambo for many years, notes that "Thabo's style was more closed than OR's. OR was never competitive . . . [but] Thabo has had to fight for leadership, consciously or unconsciously, and therefore he is much more of a closed person."

Any young man who aspires to leadership has to fight for that position, even if he is so fortunate as to be blessed with the name Mbeki. But each combatant responds differently to the battle and its results. To understand Thabo Mbeki, one needs to recognise that he still bears scars from these battles and that he has developed, as a result, a carapace of caution, even - some in the ANC say - of paranoia.

Watching the President-elect on stage at Gallagher Estate on Thursday, one was struck, certainly, by the way he controlled his emotions. One was struck, too, by the observation that nothing lifts a shield more effectively than a decisive victory.

With acknowledgements to Mark Gevisser and the Sunday Times.