Almost a year after Aung San Suu Kyi's release from house arrest, Burma finally seems to be on the path of reform. A series of highly symbolic moves, starting in August with an invitation to the democracy leader and Nobel Peace Prizewinner to meet the new president, culminated this week with a significant release of political prisoners – one of the opposition's key demands. But if both Suu herself and the outside world react with caution, it is understandable. Burma has been down this road before, and has been bitterly disappointed. The elections which brought the present, notionally civilian government to power were widely condemned as fraudulent; the president himself is a former top general; and standing behind him are the monstrously corrupt generals, headed by former Senior General Than Shwe, who ransacked the country while amassing vast wealth.

The first time Suu was released from house arrest, in July 1995, after nearly six years, she was barred from leaving Rangoon. She was detained again in September 2000, but when she was freed in May 2002, the UN's Special Envoy, Razali Ismail, persuaded Burma's military junta to agree not merely to let her leave her home but to go wherever she chose. It was widely believed that the regime was keen to open negotiations with her party, the National League for Democracy (NLD): her release, granting her full freedom to travel, was seen as the first step.

She wasted no time putting the agreement to the test. She took her democracy show, which had galvanised the country in 1989 at the start of her political career, back on the road, travelling to every corner of the country. But the epic journeys very nearly ended in her death.

When Suu started travelling again in 2002, it was as if she had never been away, as if nothing had happened in the 13 years since her last election campaign trip in May 1989. If anyone supposed that the Burmese masses had forgotten all about their heroine in the intervening years, it was a rude awakening. As videos shot during her meetings prove, everywhere she went the crowds were again vast, and vastly good-humoured. Her tours in 1989 had been the most dramatic political manifestations in Burma's independent history, the most vivid demonstrations, nationwide, of the strength of opposition to the junta and the strength of support for her. The re-runs in 2002 and 2003, despite the passing of the years, were no less so.

But this time around there was a sinister new element. One of the initiatives taken by Senior General Than Shwe after taking power in 1992 was the creation of a mass organisation to counter the influence of Suu's NLD. The Union Solidarity and Development Association (USDA) was the military's civilian proxy: its means of securing the allegiance of millions of ordinary Burmese at every level of society by giving them favourable access to services and facilities, ranging from paved roads to courses in computing, from which the masses of those who don't belong are excluded. Last year the organisation mutated into the Union Solidarity and Development Party (USDP), which is now Burma's notional ruling party.

Both the USDA and USDP have their respectable faces, but there is another side that is not respectable at all. When occasion demands, the USDA provides hoodlums, thieves, drunks, drug addicts and other men with nothing to lose with the weapons and training to do the dirty jobs which k the regime does not care to entrust to regular soldiers. The USDA can rapidly mutate into a force of mercenary vigilantes, given a vicious edge by opening the gates of the jails, offering drink, drugs, crude weapons and meagre bribes to the inmates, then sitting back and watching the mayhem.

Suu had long experience of their tactics. "The USDA has become a very dangerous organisation," she said back in 1996. "It is now being used in the way Hitler used his Brownshirts... [it] is being used to crush the democratic movement." The same year, when Suu and her colleagues were driving from her house in University Avenue to address a meeting nearby, a USDA gang attacked the car and smashed the windows; two years later, other thugs from the organisation forced her car off the road. And during her new tours of the country, this shadowy militia dogged Suu and her colleagues every step of the way.

The trips had begun in June 2002. Suu travelled in a new Toyota Land Cruiser, and to counter the USDA threat, her team included a significantly larger number of student bodyguards than previously. They criss-crossed the country, visiting 95 cities, towns and villages. Then, on 29 May 2003, she left the northern city of Mandalay, heading west to the town of Monywa.

The journey was planned as carefully as a military manoeuvre – which in a sense it resembled, despite the authorities' formal approval of the itinerary. Suu had warned her companions that if they were attacked by the USDA, they were not to retaliate. So their only hope of safety was in careful planning, and in numbers.

Wunna Maung, one of her bodyguards, said later in testimony to the US Congress: "Before our journey we heard many rumours that local officials of the military regime were training their troops with blunt weapons, including clubs, spears and iron spikes. For this reason, Daw Suu [literally, Aunt Suu, an honorific title] advised us absolutely to avoid any words or behaviour that might lead to confrontation with any members of the military. She told us that if we were attacked we must not fight back. Even if we are struck or killed, she said, we should absolutely not fight back."

Suu was well aware of the potential danger they faced. During one of the most tense periods of her previous spell of freedom, in November 1996, the secretary of the USDA, U Win Sein, who was also Minister of Transport, had told a meeting of villagers near Mandalay that killing Aung San Suu Kyi was their duty. Daw Aung San Suu Kyi, "the creator of internal political disturbances" must be "eradicated", he said. "Do you understand what is meant by eradicated?" he asked them. "Eradicated means to kill. Dare you kill Daw Suu Kyi?" Villagers within earshot later testified that he repeated the question five or six times but received no reply.

Given this high-level interest in her elimination, Suu was taking no chances. At 9am on 29 May, seven NLD cars and 20 motorcycles rolled out of Mandalay on the road west. In the lead, a few hundred yards ahead of the rest, was a scout car; next came Suu's dark-green Toyota, driven by a law student and party member called Kyaw Soe Lin, followed by two other cars filled with senior NLD figures, including party vice-chairman U Tin Oo, then the cars of local supporters. The group consisted of about 100 people in all.

The trouble that awaited them had been carefully prepared. Starting six days earlier, the military authorities in the area, under the command of plump, pasty-faced Lieutenant Colonel Than Han, had mustered local USDA members from townships around the town of Shwebo, 100km north of Mandalay, a total it is claimed of about 5,000 men, and brought them to the grounds of Depayin High School along with more than 50 lorries and 10 pick-up trucks, to train them for the assault. On the day of the attack they were issued with their weapons: bamboo staves, baseball bats, sharpened iron rods, and similar crude implements, many of them specially made by a local blacksmith.

After spending the night at a supporter's home and making a speech in the centre of Monywa, Suu did as she had been doing up and down the country and re-opened the local NLD office. Then she and her party set off again, bound for Shwebo district, 50km to the north-east.

As usual, they had obtained full authorisation for this journey in advance. But as the jabs and taunts of their enemies intensified, they must have felt like an army patrol travelling through hostile guerrilla country: never sure when the next attack would come or what form it would take.

And now, as they approached Depayin township, the army joined in the harassment. "When Daw Aung San Suu Kyi arrived near Zeedaw village," an eyewitness later testified, "military authorities from the Northern Command headquarters stopped the convoy, including the cars of the people of Monywa who had come to see them off." Suu and her party were permitted to proceed, but when her supporters returned later to the same village on their way back to Monywa, "the police waiting in readiness beat them up and put them under arrest".

Unaware of this, Suu and her team drove on to the town of Butalin, where she once again performed the ceremonial re-opening of the local party office. They were now deep into the flat paddy fields of the countryside, far from any sizeable town and even further from the gaze of foreign diplomats and journalists. They stopped at the little town of Saing-pyin, where Suu had an emotional encounter with the family of the local NLD MP-elect, who was still serving a jail sentence. Meanwhile, her minders sent a car on to scout the road ahead. Ominously, it failed to return. Motorcycles were sent to find out what had happened to it. But they, too, disappeared.

Still miles from their destination, with darkness closing in, Suu and her team were driving blind into terra incognita, with a hostile army presence behind them and no way of knowing what lay ahead. By the time they arrived at the little village of Kyi, it was pitch-dark. They had not planned to stop here, but a little way beyond the village the headlights of Suu's car picked up two elderly monks sitting on the roadside, who hailed them as they approached.

"They asked if Suu could address a gathering," Kyaw Soe Lin, her driver, recalled. "I told Daw Daw Suu that we shouldn't stop, as we usually get harassed around dusk. But the monks said they had been waiting for Suu Kyi since the evening before and requested that she give a speech and greet them." To turn down such a request from two old monks would be the height of bad manners, whatever the circumstances. Suu fell into the trap. According to Kyaw Soe Lin, "Daw Daw said we should stop for them."

The old men were not monks at all, but imposters from the USDA. And as the convoy halted on the road while Suu decided how best to accede to their request, the full fury of the USDA fell upon them. Four vehicles which had been tailing them, two lorries and two pick-up trucks, now roared up alongside the convoy and armed men poured out, shouting anti-Suu slogans. When the local villagers, who had come out of their houses to see what was going on, started shouting back at them, the USDA thugs attacked them with iron rods, bamboo staves and baseball bats. One of the USDA lorries took a run at the villagers in its headlights, and the villagers scattered in terror – whereupon a much larger USDA force – 4,000, according to some eye-witnesses, though the figure is impossible to verify – who had been waiting to ambush the convoy poured from the sides of the road and attacked the NLD cars and their motorcycle outriders and local supporters.

"We watched helplessly and tried to show courage," said Wunna Maung, the bodyguard. "Because we had been told to never use violence, we tried to protect Suu's car by surrounding [it] with our bodies in two layers. As we waited, all the cars behind us were being attacked, and the USDA members beat the NLD members mercilessly. The attackers appeared to be either on drugs or drunk.

"The USDA members struck down everyone, including youths and women. They used the iron rods to strike inside the cars. I saw the attackers beat [NLD vice-chairman] U Tin Oo and hit him on the head before they dragged him away. He had a wound on his head and was bleeding.

"The attackers beat women and pulled off their longyi [skirts] and their blouses. When victims, covered in blood, fell to the ground, the attackers grabbed their hair and pounded their heads on the pavement until their bodies stopped moving. The whole time, the attackers were screaming the words, 'Die, die, die...' There was so much blood. I still cannot get rid of the sight of people, covered in blood, being beaten mercilessly to death."

What saved Suu's life, according to Aung Lynn Htut, a senior military intelligence officer who later defected to the United States, was that the officers in charge of the attack had not expected her car to be at the front – which was why the initial attack was concentrated on the cars in the middle and the rear. But it was not long before they realised their mistake.

"As the USDA members approached Daw Suu's car, we braced ourselves for the attacks," Wunna Maung recalled. "The attackers first beat the outer ring of my colleagues on the left side of Daw Suu's car, and smashed the window... As my colleagues collapsed one by one, the attackers then started beating the inner ring of security. The attackers hit my colleagues ferociously, because they knew we would not fight back." Wunna Maung was saved only because he was on the right side of the car, while the attacks were concentrated on the left.

Inside the car, Suu's driver pleaded with the attackers, telling them who exactly he was carrying in the back – but that only inflamed them further. "My anger exploded," he admitted, "I wanted to run them over." He put the vehicle into reverse, stamped on the accelerator and the car hurtled back; the assailants reacted by raining blows on the car, breaking the windows both in the front and the back, where Suu was travelling, as well as the wing mirrors and the headlights, and battering the car's bodywork.

Over his shoulder as he roared backwards, Kyaw Soe Lin saw wounded colleagues sprawled across the road, in his path; frightened that he might run them over, he again reversed direction – but now the road ahead was blocked by trucks. Pulling over to the verge he succeeded in squeezing past them, but then found himself faced by dozens more trucks, their lights illuminating more attackers – 200 to 300 was his estimate, some holding banners with anti-NLD slogans.

The USDA men looked on "in surprise", he said, as he hurtled towards them. Some of his party's bodyguards were clinging to the outside of the vehicle, hanging on for dear life. "I was worried that the attackers might pull them off if we got too close," he said, "so I drove straight at them, pretending I was going to run into them, and they scattered. Then I pulled the car back on to the road and kept driving."

In the murk ahead he saw more roadblocks, but resolved to get through them without stopping. "I realised that all of us, including Daw Daw, would die if we didn't get out of this place, so I kept on driving." As he roared through the hostile mob they threw objects at the car, smashing the remaining windows, and one of them striking him. "Daw Daw asked me if I was OK. I said I was fine and kept on driving. I knew that if I stopped at the road blocks they would beat us to death." He wove through another barricade of trucks and past a line of police with their guns pointed at the road, and other figures with guns who looked like soldiers. "I drove through them but didn't hit anyone, as they jumped out of the way," he recalled. "Daw Daw said we should stop only when we reached Depayin."

But they didn't make it that far. As they entered the town of Yea-U, armed guards forced them to stop, demanded to know who was in the car, and made them wait. Half-an-hour later a large contingent of soldiers turned up. "One officer, apparently a battalion commander, arrived and put a gun to my temple and ordered us to go with them," Kyaw Soe Lin said. "Daw Daw nodded at me, so I did as they said. We were taken to Yea-U jail." Suu's year of freedom – her year of living more dangerously than ever before – was over.

WHAT HAPPENED NEXT

Suu survived the Depayin massacre without serious injury, thanks to the courage and skill of her driver, but it cost the lives of about 70 of her supporters. She herself was first put in jail and then, after protests from the UN Envoy Razali Ismail, sent back to house arrest. For the outside world, and for most people in Burma, too, Depayin was a major setback. The hopes for a negotiated return to democracy that had been raised with her release from detention in May 2002 were dashed.

But the true story was not that simple.

Soon after the attack, Senior General Than Shwe admitted having ordered it: in a letter to Asian governments he justified it by claiming that Suu and her party were "conspiring to create an anarchic situation... with a view to attaining power". But when the US tightened sanctions and Japan, the regime's most reliable friend, suspended aid, it became clear that the assault had been a colossal mistake, and its failure a personal humiliation.

To recoup some ground he promoted military intelligence chief Lieutenant General Khin Nyunt, the third man in the ruling triumvirate and the man who had pushed for talks with Suu, to prime minister. Khin Nyunt announced a "seven-point road map to democracy", intended to produce a constitution and elections. He then launched the regime's first-ever serious negotiations with Suu, so secret that their existence emerged only after Suu's release last year

After a number of meetings, the two sides were close to agreement: "We were almost there," Suu revealed last November. But when Khin Nyunt presented Than Shwe with the deal, the Senior General took fright. Both Khin Nyunt and the brigadier who had led the negotiations were purged and jailed, and Burmese politics went back into the deep freeze. Another six years were to pass before Suu was released.