On 12 November 1912, a party of British explorers was crossing the Ross Ice Shelf in Antarctica when one of the team, Charles Wright, noticed "a small object projecting above the surface". He halted and discovered the tip of a tent. "It was a great shock," he recalled.

With his companions, Wright had been searching for Captain Robert Falcon Scott who, with four colleagues, had set off to reach the South Pole the previous year. The team, from the Scott expedition base camp, knew their comrades were dead: their provisions would have run out long ago. But how and where had Scott perished?

Wright had found the answer. "I tried to signal my party to stop as I considered it would be a sort of sacrilege to make a noise," he said later. The men began digging and revealed a tent, perfectly pitched, as Scott would have insisted. He was lying at its centre with Lieutenant Henry Bowers and Dr Edward Wilson on either side. His companions appeared at peace but Scott looked agitated, as if he had struggled to the last. Of his other men, diaries showed that Petty Officer Edgar Evans had suffered concussion after a fall and died a few weeks after the group began trudging back from the pole, while Captain Lawrence Oates had walked out of their tent to his death because he felt that he was holding back his comrades. Those diaries also showed that Scott had been beaten to the Pole by the Norwegian Roald Amundsen.

The cold had turned the skin of Scott, Wilson and Bowers yellow and glassy. "That scene can never leave my memory," recalled Apsley Cherry-Garrard, another search-party member. "We never moved them. We took the bamboos of the tent away and the tent itself covered them. Over them we built the cairn." The party's leader, Edward Atkinson, read the lesson for the burial service from Corinthians.

It took three more months for the expedition's survivors to reach New Zealand and to cable Britain. Four days after the news arrived, a memorial service was held at St Paul's, attended by the King, the Archbishop of Canterbury and the elite of British society. More than 10,000 people gathered outside. Just as it did when Princess Diana died, Britain reacted with an outpouring of national grief.

Over the following century, Scott's death provided Britain with a powerful legend imbued with heroism, sacrifice – and a noble defeat that will be the focus of considerable attention when, on 14 December, the 100th anniversary of the South Pole's conquest is commemorated. On that day, at exactly 3pm, Amundsen and his four companions reached the planet's most desolate, inhospitable spot. Amundsen noted in his diary: "We had a celebration dinner: a small piece of seal meat each." Thirty four days later, Scott arrived and found that his greatest fear – to be beaten to the pole by the Norwegian – had come true. "Great God! this is an awful place and terrible enough for us to have laboured to it without reward of priority," he wrote.

Amundsen's victory and Scott's defeat have acquired a mythic status over the years: a battle between cold, Scandinavian efficiency and British have-a-go pluck and cheery amateurishness. The victory of the former was therefore assured, it is assumed, while the latter was doomed from the start.

'A chain of events – and lies – put Amundsen there. He should have been at the other pole.' Scott in his naval uniform and Roald Amundsen. Photograph: Getty

In fact, the arrival of Amundsen at the South Pole that day was by no means a certainty, a point that remains one of the least appreciated aspects of the Scott-Amundsen story. Indeed, it had taken an extraordinary chain of events – and lies – to place Amundsen there. By rights, he should have been standing on our planet's other pole that year. From this perspective, Scott was a victim, not simply of bad luck but of deception. As UK polar expert Nick Cox says: "Only the slightest change in circumstances could have produced a dramatically different outcome for Scott."

Roald Amundsen, the fourth son of a family of Norwegian ship owners, had been fascinated since adolescence with the fate of Sir John Franklin's lost expedition to find the Northwest Passage, a sea route that would link the Atlantic and Pacific oceans. He was also inspired by the great Norwegian explorer Fridtjof Nansen, who had come close to conquering the North Pole in 1895. Amundsen vowed to achieve the goals that had eluded his two heroes. In 1900, aged 28, he used up his inheritance to buy the shallow-hulled ship Gjoa which he then sailed through the knots of tiny islands, ice floes and shoals of northern Canada from the Atlantic to the Pacific. The Northwest Passage had been conquered. Amundsen turned to the North Pole and his hero, Nansen, agreed to lend his ship, the Fram, for a new expedition. And then the bombshell dropped.

Within weeks of each other, in 1909, two rival US explorers – Robert Peary and Frederick Cook – announced they had led two separate expeditions to the North Pole. Neither man's claim is accepted today, so poor was their proof of arrival and so incredible were the speeds with which they claimed to have travelled over the ice. Even at the time, there were mutterings. Both were backed by rival New York newspapers, it was noted. But it was enough for Amundsen. There was no glory in going north, he decided. Robbed of one pole, he simply chose to bag the other. But there were complications: Robert Scott, the 42-year-old who had already led one expedition to Antarctica from 1901 to 1904, was preparing to embark on a new voyage there.

"Norway had only just achieved independence and its biggest ally in gaining this had been Britain," says Geir Klover, director of the Fram Museum in Oslo. "Our queen, Maud, was British, the granddaughter of Queen Victoria." Protocol indicated that Scott's expedition should not have to face a last-minute Norwegian rival. Amundsen knew this and was aware he would probably be refused permission to use the Fram to go to Antarctica. So he sailed off from Oslo, on 3 June 1910, with the professed intent of sticking to his old plan to sail the Fram round Cape Horn and back north to Alaska and the easier route to the North Pole.

Only when he reached Madeira, while Scott was on his way to Australia, did Amundsen reveal his new plan. A telegram awaited Scott in Melbourne: "Beg leave to inform. Fram heading south. Amundsen." The news stunned Scott and his men. As one of them remarked: "We are up against a very big man." This view is backed by Klover: "Amundsen had a tremendous reputation. He was a meticulous planner, easily the best organised explorer of his generation. It was not good news for Scott."

Yet it had taken a series of deceptions to send Amundsen on his way to clash with Scott. "If Peary and Cook had not been believed, then Amundsen would not have lied and headed south," says Cox. "Scott would not have got to the South Pole any quicker, but his party's return – having been first to the pole – would have been a far more spirited, cheerful affair. Scott, Bowers and Wilson died 11 miles short of a huge food depot. They just might have made that with the spring of victory in their steps."

As it was, Scott now had to contend with a race to the pole in addition to the complex scientific missions he had planned. Apart from the expedition's geological, meteorological and biological goals, he had included ponies, dogs and mechanical sledges to try out each one's transport potential and carry out many other tests. By contrast, Amundsen merely telegrammed the scientists he had promised to collect in San Francisco en route to the North Pole and told them not to bother. "Amundsen was keen on science, but not on this expedition," admits Klover. Unencumbered, his teams of dog sledges swept easily to the pole. By contrast, Scott refused to give up a single scientific goal and that cost his men dearly.

The ice men: Scott, seated at the far end, celebrates his 43rd birthday during his Terra Nova expedition to the Antarctic, 6 June 1911. Photograph: Scott Polar Research Institute



Thirty miles north of London, at Tring in Hertfordshire, the Natural History Museum has one of its most important collections. Eggs from more than half of the world's 10,000 bird species are stored here, from giant specimens provided by ostriches to tiny hummingbird eggs. It is an astonishing array and involved a great many individuals undertaking hazardous missions to collect them. However, none endured the hardship of the men who gathered the collection's greatest prize: three emperor penguin eggs that are kept in a cardboard shoebox-sized container labelled "Aptenodytes forsteri, Cape Crozier, 20 July 1911" and stored in one of the hundreds of cabinets lining the museum's walls.

"At the time, it was thought the emperor penguin was one of the planet's most primitive birds," says Douglas Russell, Tring's curator of eggs, "and that analysis of its embryos would allow scientists to peer deep into the evolutionary history of all birds and establish links between them and their reptile predecessors. All that was needed were some fresh-laid emperor penguin eggs." It sounded uncomplicated and appropriate for Scott's mission. There was a catch, however. The emperor penguin lays its eggs in June, in the Antarctic midwinter.

No one had ever travelled in Antarctica during winter. But Scott's chief scientist, Edward Wilson, thought it would be straightforward and enlisted Bowers and Cherry-Garrard. If nothing else, the egg-collecting trip fitted in perfectly with Scott's goals. He recruited specialists in zoology, geology, physics and meteorology to take part. From the start, he had insisted research was to be the main purpose of his expedition. Bagging the pole would merely be a bonus, he claimed. Thus Scott established a substantial base camp on Ross Island when he arrived in Antarctica and arranged for his men to carry out several other mapping and geological missions while he made a bid for the pole. Of these other missions, the one led by Victor Campbell to the north would be the most arduous – with the exception of the journey taken by Bowers, Cherry and Wilson.

At midday on 27 June 1911, the trio left their base-camp hut – and walked into a freezing, pitch-black, gale-battered nightmare. The men had to pull two sledges of food, fuel and equipment to reach the penguin's breeding colony at Cape Crozier, 70 miles away. Temperatures plunged to -60C while the thick cloying snow forced them to pull their sledges in relay, so they gained only one mile for every three they walked. They could only navigate by moonlight or by the dim twilight around noon. The rest was utter darkness. The men took turns falling into crevasses. At one point, Cherry's teeth chattered so violently they shattered. "Sometimes it was difficult not to howl," he recalled in his aptly titled account of the expedition, The Worst Journey in the World.

The trio eventually found the colony, snatched six eggs, dropped three and staggered back to base camp close to death. "Their faces were scarred and wrinkled, their eyes dull, their hands whitened and creased," Scott noted. For five weeks, the men had endured the hardest conditions on record, he added. Cherry never fully recovered. As to the eggs, after the death of the scientist they were intended for, they were passed around until 1934 when zoologist CW Parsons concluded, "They did not greatly add to our understanding of penguin embryology." For good measure, scientists no longer believe that embryos help much in studying a species' evolutionary history. Science can be a harsh mistress.

Yet in many other ways, Scott played a key role in opening up Antarctica to scientific scrutiny. He used mechanised sledges – the only aid Amundsen feared might win the race for Scott. The sledges failed, but the lessons learned were crucial to their use in future expeditions. The meteorological readings made by his team provided science with the longest unbroken measurement of weather in Antarctica and are still used today. "Scott's expedition also brought back 40,000 specimens and their research produced 15 volumes of bound reports written by 59 specialists," says Elin Simonsson, of the Natural History Museum in London. "The birth of glaciology can be traced to the expedition while the photography of Herbert Ponting transformed the use of cameras on other expeditions."

The most important of all specimens returned was one of the last to be collected. On 12 February 1912, as his team trudged, defeated from the pole, Scott stopped at the top of the Beardmore glacier and, noting some interesting moraine, decided it would be a good day to spend "geologising". Incredibly, they added 35lb of rocks to their load, an act that is seen by Scott's critics as an act of utter folly. Roland Huntford describes it as "a pathetic little gesture to salvage something from defeat at the pole" (see box above).

Certainly, it seems an extraordinary move, wasting time and adding weight to sledges that were difficult to haul. Climate expert Professor Jane Francis of Leeds University disagrees. "I have worked on the Beardmore glacier. On a sunny day, it is a beautiful place. Scott was probably giving his men a rest before the last trek home. And the weight would have made little difference to the energy they expended."

Whatever the reason, it was a providential decision. Among the rocks, scientists found a fossil sample of a Glossopteris fern. "Glossopteris has big feather-shaped leaves and Scott and his men found a very small fragmentary piece. But it was a very important find," says palaeontologist Paul Kenrick of the Natural History Museum in London, where the Scott Expedition's myriad fossil samples are stored. "The plant is extinct, but fossils had already been found in Australia, South America and India. Its discovery in Antarctica provided key support for the idea that all these continents had once been linked together in one vast supercontinent, a theory we now know to be correct."

This success was the last moment of relief for Scott and his men. Edgar Evans, the team's strongest man, had already begun to weaken. On 17 February, Scott found "the poor man… on his knees with clothing disarranged, hands uncovered and frostbitten, and a wild look in his eyes." Evans died that night – probably of brain damage, incurred during a fall, and aggravated "by scurvy, dehydration, high altitude, or a combination of all these factors", states atmosphere chemist Susan Solomon.

A monument erected to Scott in 1912 in the French Alps where he had tested dog sledges for his expedition; and the last page of Scott’s journal. Photograph: Getty

Oates was next. Lame from frostbite, he could hardly walk and had his reindeer-skin sleeping bag slashed on one side so he could keep his leg outside so it would freeze and kill the pain. He asked Scott to leave him to die, but was refused. By 16 March it was obvious he could not go on and he walked out of the tent, into a blizzard, to his death, an act of self-sacrifice that has achieved mythic status. It was "a luminous moment in our history", as the polar travel writer Sara Wheeler has put it. The search party that had found Scott, Bowers and Wilson in their tent later discovered Oates's effects and erected a cross there. "Hereabouts died a very gallant gentleman," it stated.

After Oates's sacrifice, Scott realised that he, Bowers and Wilson had little chance of survival. By 22 March they had two days' food left, but were three days short of their next depot. Then a blizzard struck and stopped them moving on. They never left their tent again. "We have struggled to the end and have nothing to regret," Wilson wrote to his wife, Oriana. For his part, Bowers tried to soothe his mother. "For me, the end was peaceful as it is only sleep in the cold," he told her. Scott, almost certainly the last to die, wrote copious letters to the expedition's backers, his colleagues and the families of his dead comrades. His final letter is dated 29 March. "It seems a pity, but I do not think I can write more. R Scott," he scrawled, before adding a last frantic message: "For God's sake look after our people."

Many of these letters are gathered at the Scott Polar Research Institute's museum in Cambridge, and displayed in drawers where visitors can study them. Written in pencil, they are hard to decipher, but nevertheless have a powerful impact. "I still find them intensely moving," says Heather Lane, the institute's librarian. Oates's sleeping bag is also displayed there, with its slashed-open side, another poignant reminder of the men's suffering.

As to Scott's last words, these were not a general cry of despair but a very specific call for financial help for his family, says Lane. "Scott was desperate because he knew he was the sole breadwinner, not just for his wife Kathleen and their son Peter, but for his mother and sisters. He was frantic they would be left destitute. That is why he wrote those words." In this case, he need not have worried. An appeal for funds by the Lord Mayor of London was so successful it provided pensions for all the polar party's widows and orphans, with enough left over to set up the Scott Polar Research Institute.

There is one final twist to Scott's story. Edward Atkinson, the man left in charge of Base Camp, knew Scott was dead, but had no idea what had happened to a second expedition led by Lieutenant Victor Campbell to survey the coast to the north. (He and his men had become trapped by the Antarctic winter, but survived for months in blubbery filth by sheltering in a cave they carved out of the ice.) As the weather improved, Atkinson had to decide: should he try to find Scott's or Campbell's party? The former were certainly dead while finding Campbell could make the difference between life and death for his men.

Atkinson held a vote. There was one abstention. The rest voted to find Scott. "It says everything about Scott and his centrality to the whole expedition, that not a single man spoke up for the living," notes his biographer David Crane. If the search party had failed to find Scott, and if Campbell and his men had died, their names would have "stunk to the heavens", Wright noted at the time.

But Campbell survived and the bodies, letters and diaries of Scott and his men were found. As a result, our perceptions of the Antarctic were changed for ever. We learned of Oates's sacrifice, the death of Evans, and the final, terrible days the last three survivors had to endure before they lay down to wait for death. (They had enough morphine to kill themselves, but decided to die naturally.) We also learned of Scott's last words and read the desperately poignant letters he wrote to his comrades' families and to his own loved ones. "Had we lived, I should have had a tale to tell of the hardihood, endurance and courage of my companions which would have stirred the heart of every Englishman," he wrote. "These rough notes and our dead bodies must tell the tale."

As the explorer Ranulph Fiennes says: "Scott wrote wonderful English under awful circumstances." Crane goes further: "His letters, diary and last message extend our sense of what it is to be human. No one else could have written them; no one else, at the point of defeat and dissolution, could have so vividly articulated a sense of human possibilities that transcend both." As to the fate of Scott's body, and those of Wilson and Bowers, the impromptu mausoleum created by Cherry, Atkinson and the rest of the search party has long since disappeared, says Lane. "The cairn with their bodies is still out there on the Barrier, deeply buried under accumulated snow, heading slowly towards the Southern Ocean as the ice fields move towards the sea – where they will eventually receive a marine committal."

Scott's Last Expedition opens at London's Natural History Museum on 20 January. The Scott Polar Research Institute in Cambridge is also running a series of exhibitions and events to mark the centenary over the next 12 months (spri.cam.ac.uk/museum)