"Those Chinese f@# !ers are trying to rat-f@#! us," declared Kevin Rudd. As snow fell on Copen-hagen - on its palaces and squats, on police and their dogs, on protesters rugged up against the fierce cold and on the big, bland Bella Centre where the largest gathering of world leaders in history sulked and plotted - the prime minister of Australia faced the collapse of old dreams.

This was the little boy fascinated by China, the kid who longed to be a diplomat, the man who believed a better world might be built through international agreement, and a prime minister struggling to meet "one of the greatest moral, economic and environmental challenges of our age".

Life had brought him, inevitably it seemed, to this icy Scandinavian city a few days before Christmas 2009 and he blamed the Chinese for wrecking it all.

The Copenhagen that mattered began on December 17 and lasted 40 hours. Rudd slept for one of them. He wasn't shy. He relished working with the big boys. Almost to the very end he was a player in the meetings that mattered.

After Queen Margrethe's state dinner at the Christiansborg Palace - Rudd so monopolised Princess Mary's attentions that British prime minister Gordon Brown on her other side was left staring at his plate - he joined France's Nicolas Sarkozy, Germany's Angela Merkel, Brown and another 20 world leaders in free-wheeling and futile efforts to find agreement. At 3am they left the haggling to their environment ministers.

By this time delegates were sleeping on sofas all over the Bella Centre. Rudd had an hour's kip in an armchair, all he felt he needed to keep going.

Tired and exasperated, surrounded by a knot of Australian officials and press, Rudd began to rage against the Chinese. He needed sleep. His anger was real, but his language seemed forced, deliberately foul.

In this mood, he'd been talking about countries "rat-f...ing" each other for days. Was a deal still possible, asked one of the Australians.

"Depends whether those rat-f...ing Chinese want to f... us." Barack Obama postponed his departure a few hours. At nightfall on an already endless day, the leaders of the 26 nations met again, with Chinese

premier Wen Jiabao once more pointedly absent.

In The Guardian, Mark Lynas reported the Chinese blocking every initiative: " 'Why can't we even mention our own targets?' demanded a furious Angela Merkel. Australia's prime minister, Kevin Rudd, was annoyed enough to bang his microphone."

The bones of the Copenhagen Accord were decided that evening in a meeting between the US, China, India, Brazil and South Africa. Rudd was not there. Their bare deal was sent on to Rudd's group of leaders. Meanwhile, Obama briefed the US press and flew out on Air Force One.

When Rudd emerged an hour later, he had to be told the world already knew the outcome. Addressing reporters with barely the energy to take notes, he declared bravely: "We prevailed. Some will be disappointed by the amount of progress. The alternative was, frankly, catastrophic collapse of these negotiations."

His efforts at Copenhagen are Rudd's answer to those who accuse him of being a bureaucrat at heart, an "incrementalist", a leader unable to dream.

He sees Copenhagen as proof that he's willing to go out on a limb, spend political capital and court trouble at home for a great cause. And Rudd insists Copenhagen was not a failure.

He is one of an unusual species: the diplomat turned leader. Though his time in the foreign service was a brief seven years, they've marked him for life. For the diplomat, negotiations have never failed so long as there's a prospect, however vague, of agreement somewhere down the track.

For someone who thinks as he does, it can be just as important to keep everyone at the table, to keep talks going, to keep hopes alive, as it is to bring great issues to a head. The rhetoric of success Rudd used in these exhausted hours wasn't all spin. It was authentic Rudd.

Rudd's bond with the people began to fray after Copenhagen. Having picked him as a leader long before he became his party's choice, Aust-ralians had held Rudd in extraordinary affection for years. Never had the polls shown a prime minister so popular for so long. But after this debacle, the mood shifted. In late April this year, when he abandoned his emissions trading scheme until the far reaches of a second term, the people and the polls turned on him savagely. His leadership was in question.

Now he has picked a brave fight with the mining companies to tax their megaprofits. A leader with a reputation for cutting and running has set himself a defining test of courage. Rudd had sold himself to the Australian people as a new kind of politician: soft-hearted, hard-headed, courageous, visionary, even pure. Fight-ing climate change brought together his political and his Christian agendas. Failure here put in question the entire Rudd enterprise. More urgently than ever, Australians were left asking: who is he?

Rudd seems to have been with us forever yet still to be a newcomer, indeed a stranger, in The Lodge. Millions of words have been written about him since he emerged from the Labor pack half a dozen years ago, but Rudd remains hidden in full view.

Leadership," rudd told me, "is always a lonely race. Anyone honest about their reflections on that reaches the same conclusion." Through hard and lonely work he won the leadership of his party. "I've always just been a person who believes in rowing his own race, that is, doing what you believe to be the right thing, doing it with vigour, doing it with conviction and doing it with determination."

Former NSW premier Bob Carr remembers the years, the determination and the work Rudd put into climbing to the top: "He nagged the party into it, kept insisting. He willed himself there. He couldn't be overlooked. He was always in your diary or at your door."

Rudd's arrival in Canberra in 1998 hadn't set caucus alight. He didn't hide his ambitions. There was only one job he was really interested in: being prime minister. To be shooting so high so soon marked him as a bit of a prat. His position was, indeed, lonely: no faction backed him and he made few friends in Labor ranks. Where, they wondered, did he fit?

What his puzzled new companions in caucus missed was the peculiarly personal nature of Rudd's political faith: a commitment to politics growing not out of history, work or ideological conviction, but out of the hell of his childhood.

For a long time, he wouldn't tell the story of the bad years that followed his father's death. That he'd grown up a dreamy barefoot kid on a dairy farm was no secret, but what happened then was something friends and colleagues knew little or nothing about. They didn't ask questions. They sensed his childhood was a no-go zone. Rudd was 45 and beginning his run for the leadership of the Labor Party before he began talking of the events that still drive his plain, conservative politics.

The Rudds were living in a neat little house on a low rise outside the village of Eumundi. Bert was share-farming for Aubrey Low, the milk and butter tzar of the district. Kevin was sickly and lived in the protective embrace of his mother. An operation at the age of three to correct his badly bowed legs left him having to learn to walk again.

Some time between the ages of five and seven, he was struck down by rheumatic fever and he found himself once again in hospital and recuperating at home for long stretches. That the fever had affected his heart was not discovered for half a dozen years. The damaged heart was on a list of dark Rudd secrets that would only emerge in a Liberal Party smear campaign before the 2007 poll. Did he have the ticker?

Bert died after a car accident when Rudd was 11. Being tossed off the farm a few months later was fundamentally humiliating for the boy. The Rudds were suddenly poor, with only the charity of his mother's De Vere relatives to fall back on. "I didn't find that a terribly dignifying experience," said Rudd. His mother found a job in a nursing home outside Brisbane and the little boy turned up halfway through 1969 as a boarder at Marist College Ashgrove in the Brisbane hills. He was a charity case: the school met the bills because Marge Rudd was known as a good Catholic.

Ashgrove marked Rudd. He emerged with an icy hatred of the school. "It was tough, harsh, unforgiving, institutional Catholicism of the old school," he told Julia Baird, on ABC radio. "I didn't like it." Was there physical abuse? she asked. "Some of the brothers whacked kids and some were actually quite kind, but it was still the culture, I think it's fair to say - and others would agree with me - which condoned violence." Not all the brothers were quite in control of themselves. Old boys talk of brothers beating children for no clear reason in a paroxysm of rage. They seemed to pick on the weak and the lonely.

Rudd has never since encouraged Ashgrove to claim him as its own. Last year he sent on DVD an official message of staggering rudeness to mark the opening of a new science block named after his old headmaster. Rudd mangled the man's name, reminded Ashgrove's old boys more than once that he was prime minister and subjected them to a brief stump speech about Labor's contribution to science education across the nation. His scorn was colossal.

School holidays were difficult. By this time his mother was retraining as a nurse at the Mater, they had no home base and the boy was conscious of being passed "from pillar to post" as they moved between friends and De Vere relatives. On perhaps two or three occasions, there was nowhere for them to stay. Marge pulled the VW Beetle over to the side of the road and they slept in the car. The boy thought to himself: "It doesn't get much crooker than this."

He escaped Ashgrove after two years. His mother, having finished her training, found a job in Nambour, bought a fibro cottage and brought her youngest child home in the winter of 1971.

The move to Nambour High was not an immediate success. He arrived at the jumble of class-rooms on Coronation Avenue a little fearful of what might befall him as he once again finessed his way around a hostile playground. But the gears meshed in his last year. When school resumed, the teachers discovered a boy implacably determined to succeed.

"I have never met a mind like Kevin Rudd's in 40 years of teaching," recalls Fae Barber. "He was cherubic, sitting in the front row just waiting to absorb knowledge. To this day, I love and admire him." And he counts her one of the great influences on his life. He immersed himself in his work. He read. He questioned. He imaginatively entered the worlds Barber took him to: literature and ancient history. "I remember teaching him about Caesar's troubles with Pompey the Great, and young Kevin was angered by Pompey's poor behaviour."

This was more than mere swotting. He was determined to rebuild himself from the ground up. This would be a new Kevin Rudd, not the vulnerable kid who had suffered what he called "a deep sense of loss of dignity" since the family was thrown off the farm. Not the boy who had been shocked by the violence of Ashgrove. With steely determination, he would rise above the wrongs of these past years and make a big life for himself. The aim was to become unassailable.

As early as his final year at school, Rudd began to have glimmerings of political ambition. In these heady years, young Australians fell in love with Labor because Gough Whitlam promised to renew their nation's stale society. Young Rudd's infatuation had another cause. He saw Labor as a gateway to the world: the party that allowed Whitlam his triumphs in China.

The boy had been glued to the television set in 1971, mesmerised by the feting of the Labor leader in Beijing. Even at the age of 13 he had sensed he was watching a great man at an extraordinary moment. That single event still illuminates his political imagination. Forty years later, as I'm walking along the beach in Mackay with him, he exclaims: "What leadership!"

The boy's political ambitions were vague, indeed barely formed, but they lay beneath all the others. He would have to be something else first and see what political opportunities opened up to him. He took a year off to decide that that something else would not be law, but diplomacy. The boy Frankenstein of Nambour planned yet another transformation of himself: he would make his way towards that career by studying Chinese. He turned up at ANU at the beginning of 1976.

Rudd didn't lift a finger for Labor in the high political excitement of Malcolm Fraser's early years. He didn't march in the streets against Whitlam's nemesis, the governor-general Sir John Kerr, or man the booths in the election campaigns of 1977 and 1980. The wild politics of the campus held no fascination for him.

He found purpose in another quarter altogether. He led a group of evangelicals called the Navigators, intent - or so it seemed to other students - on imposing a puritan rule on Burgmann, the college where he lived. The Navigators were particularly worried about liquor - Rudd is remembered as a serial complainer about booze being sold in the college bar - rock music and fornication. Philip Hurst, an international lawyer who was then a fellow student at Burgmann, remembers fresher Rudd vividly: "He would walk down the corridor and in his wake like ducklings after a mother duck were his Christian acolytes."

His first-class honours degree opened the door to the Department of Foreign Affairs in January 1981. Later that year, as they were about to leave for a first posting in Stockholm, Rudd and Therese Rein - fellow Christian, fellow Burgmann student - married at St John's, the old church near the War Memorial where Canberra's powerful pray. Rudd had signed up to his wife's elastic, Establishment Anglican faith. And at last he joined the Labor Party.

Hundreds of us were trapped under Brisbane's Suncorp Stadium in a rowdy piece of community theatre called Waiting for Kevin. Everyone was shouting. No one could be heard. Cameras flashed like firecrackers. Up on the big screens, the ABC's Kerry O'Brien was tolling through the count like an old priest saying mass. No one was listening. A little after 7pm Queensland time, the premier, Anna Bligh, appeared from the party's headquarters upstairs and walked through the melee confiding to those in her path: "Kevin Rudd is the prime minister of Australia."

Men with wires in their ears appeared from nowhere, generic rock'n'roll pumped out of the speakers and Rudd was among us. The room responded with a mighty roar as he and his family climbed onto the platform: "Kevin. Kevin. Kevin." Therese Rein was ecstatic. The pride of the children in the face of this ovation was heart-stopping. Then Rudd killed the party.

"Okay, guys," he said, holding up his hands like a slightly weary teacher to shush the rowdy enthusiasm. "A short time ago, Mr Howard called me to offer his congratulations ..." Such courtesies are obligatory, of course, but Rudd went on and on about the virtues of his fallen opponent. The revellers waited him out: waited to burst back into life; waited for the moment when Rudd's face would break into a smile of triumph; waited for him to lead the celebrations. That never happened. The rhetoric was leaden. He lost the crowd. As he ploughed on, Rein's face fell.

Nine years earlier, when he spoke for the first time in parliament, he began with the words: "Politics is about power." Now he had power. He appeared profoundly satisfied but unable to share that satisfaction. This was about him. If his long pursuit of power was about repairing the wreckage of his childhood, then at this moment all the bits and pieces of Kevin Rudd were coming together at last. But the sight of Rudd in power was strangely discomforting.

The klieg lights went out. The cameras packed up. The screens fell silent. That was about it for the party. Sober revellers wandered out into a warm Bris-bane night. The peculiarities of the event were passed off as a joke: that's Kevin! But at victory celebrations across the nation there were those who, however jubilant to see the back of John Howard, asked themselves: what have we here?

The most powerful and conservative Labor prime minister for more than half a century. The fundamentals of Rudd's politics haven't changed since his maiden speech in 1998. Tolling through the speech is the word "decent": life had taught him, he said, the need for decent social security, decent hospitals, decent public housing. The vision is personal and conservative. Nothing radical is proposed. Yet Rudd sees this clarion call for fine-tuning as a transformative mission. To think other-wise, he says in moments of anger, is to misunderstand him entirely. Entirely.

The pursuit of decent solutions to the nation's problems is personal, intuitive, hard to delegate. It calls for the sort of scrutiny only he can give. Marry that to a sense of indispensability that is right off the Richter scale and you have what looks like a recipe for ruin.

Rudd takes early command of top-shelf policies - the emissions trading scheme or the new health arrangements with the states - but when other policies come under attack, he requires ministers to brief him down to the smallest detail. He responds to pressure by burying himself in detail. This passion to know everything makes life around him, and the business of government, hard.

David Epstein, Rudd's chief of staff, bailed out in November 2008. He had lasted a little over 18 months at Rudd's side, trying to bring order to the chaos around the leader of the opposition and later the prime minister. Reports at the time spoke of Rudd still diving into every issue in depth, still not separating wheat from chaff, still operating in logistical confusion.

History doesn't worry much about the work practices of the great. Churchill slaved for ridiculous hours and drove his staff to distraction. No one in retrospect gives a damn. Rudd isn't Churchill and this isn't the Second World War, but what looks like dysfunction in Canberra will seem mere eccentricity if the results are worthwhile. Rudd's big brain and prodigious energy save him from many of the perils of his own hyperactivity. When his attention is engaged, he is a formidable distiller of complex information.

But those who have worked for Rudd as prime minister, as opposition spokesman on foreign affairs, and in the old days as chief bureaucrat to Queensland premier Wayne Goss, tell the same tales of confusion. One told me: "His office is chaotic. He would schedule staff meetings at bizarre times, like 10pm on a Sunday night when parliament is sitting next day. And because he is busy doing other things, the 10pm meeting doesn't start until 1am.

"He doesn't trust his advisers to give advice, so they become glorified research assistants. Because everything is on the go at once and he's interrogating the detail of everything, nothing comes out until the last minute. Bringing work to a conclusion was focused around the next media hit. He loves an announcement.

"He is a strange beast behind closed doors. He is so focused on the day-to-day tasks that he loses the social niceties. They are neither here nor there. Staff are interrogated beyond what's reasonable to expect them to know. And if you don't know, the atmosphere changes. Not a blow-up. It becomes very quiet. But he doesn't deliberately push his staff to this point.

"For all the effort, he doesn't come up with particularly interesting solutions to problems. His policy positions aren't breakthroughs, not particularly new or exciting. After all that work, they are dull."

Rudd is proudly the prime minister of fine detail. Mastery of detail ensures good policy outcomes, he told me. It ensures accountability: "The prime minister is required to answer in detail across the entire breadth of government decision-making."

So he is satisfied with the flow of business through his office? "Absolutely. There is a structural criticism here which will be levelled at any private office of any head of government, state or federal, Labor or Liberal, which has been around since time immemorial. People should read the literature."

With so much power concentrated in Rudd's hands, access to the prime minister becomes a crucial issue of government. Since before Machiavelli, courtiers have whinged about access. "It's easier to get in to see the Pope than Kevin," one disgruntled backbencher told me. "He's always rushing," a junior minister told me. "You have fleeting meetings."

At the top of the ministry is a small group of men and women with easy access to the boss, though it's said there are times and moods when even these heavyweights have trouble getting through the door. They are regarded as conduits to power. Defence minister John Faulkner told me: "People have come to me and said: 'Will you tell Kevin this?' It's presumed I have better access to him. But I say to them: 'You're the one who should talk to Kevin.' "

Time can also be in short supply for distinguished citizens co-opted by Rudd to pursue his visionary plans for the future. "There comes a point when these big ideas need prime ministerial time, and it isn't there," I am told by Richard Woolcott, Rudd's special envoy to the Asia-Pacific community. "It's a disjunction."

He can be so good: turning up without fuss at a bedside or a funeral; sitting on the floor at the 2020 summit; delivering the Apology; staying on to yak with the party faithful; beguiling a table of distinguished Americans at lunch or a bunch of weary doctors in a hospital courtyard; posing time and again for photographs with families and kids when he's out walking; or dazzling a delegation from the China National Peking Opera Company with half an hour's patter in Mandarin.

And he can be so bad. He has a way of ignoring people once their usefulness is past. Before his challenge to Kim Beazley for the leadership of the opposition in 2006, he was ringing John Robertson of Unions NSW half a dozen times a day. With victory, the calls stopped. Text messages to journalists who this self-confessed media tart had courted for years dried up when he became prime minister. Something of this was inevitable: prime ministers have new and onerous preoccupations. But his neglect of obvious courtesies is a strange flaw in a politician so determined to do his chores perfectly. He switches on and switches off. Perhaps other people's feelings are a closed book to him.

He stands on his dignity. He makes a display of little grudges. He is untroubled by the impact of behaviour that is, by any measure, startlingly rude. The party has not forgiven him for failing to turn up to the funeral of John Button, one of Labor's favourite sons, in April 2008. He took a teddy bear instead to the bedside of Cate Blanchett. The sight of Rudd shuffling his papers as the NSW premier, Kristina Keneally, warmly welcomed him earlier this year became a defining bad look of his prime ministership. He and his ministers spent weeks fixing the mess with flowers, smiles and long walks through the grass for television cameras.

Everyone wishes he had more sleep. "Kevin starts at around six in the morning," Therese Rein told journalist Annabel Crabb. "He might get to bed around one or two, or maybe three. He doesn't need a lot of sleep." That's debatable. From his caucus, his office and his ministry come reports that Rudd is a better man when he has slept. The moods are better, the tantrums fewer, the work easier when he has had something like a normal night's sleep.

Moody people are judged - not always fairly - by their worst moods. When Rudd is fresh and things are going well, he turns an open face to the world. Exhausted and under pressure, he shuts down. He is a man who combines resilience and a brittle temper in quite unpredictable ways. On any day he can be both the boyish Tintin of Bill Leak's cartoons and Alan Ramsey's famous "prissy, precious prick. One with a glass jaw, a quick temper and, when he loses it, a foul tongue."

A shrewd old bureaucrat who has worked with a few prime ministers wonders if Rudd really understands the way power works at the top. He isn't afraid to pick a fight, but doesn't then behave like a prime minister: he involves himself so much; puts himself on the line so quickly; doesn't exercise authority by keeping his distance. These problems of technique are odd in a man who has had a long fascination with power. Tracking down the powerful, picking the people he has to know, began as a diplomatic duty and became a lifelong passion. He is a determined networker. But perhaps it's his deep respect for power that makes him so careful not to put powerful forces offside. His drive to acquire power is extraordinarily strong - the work of a lifetime - but he shows less enthusiasm to exercise it. His instinct is to hoard rather than spend.

If Australia saw him through Canberra's eyes, he would be done for. Though he has led until now a formidably disciplined first-term government - few leaks, only one minister lost - negotiated the global banking crisis of 2008 with exemplary skill, pulled off the great symbolic coup of the Apology and routed two opposition leaders, the capital is tired of him.

He's seen in that little world of power as a weird guy and a failing prime minister. He puzzles his caucus, frustrates his ministers and irritates the press. A habit of making endless speeches at big public events has earned the man - known at various times in his career as Dr Death, Pixie and Heavy Kevvie - a new nickname: the Castro of the South Pacific.

Colleagues from his time as the key back-room boy in Goss's reforming government have an old joke they trot out whenever they meet to talk about those days of high hopes and disappointment. They don't remember him kindly. The joke: Rudd is a creature from outer space. The proof? Who but an android would say so often, "I am only human."

Edited extract from David Marr's Power Trip: The Political Journey of Kevin Rudd, Quarterly Essay 38, published on Monday by Black Inc Books, $20.