On a bridge behind the courthouse in Kuala Lumpur yesterday morning, a crowd of several hundred angry people confronted a line of riot police in red crash helmets.
Despite a ban on demonstrations, the mostly-young Malaysians had gathered spontaneously as news spread that the former deputy prime minister and symbol of reform, Mr Anwar Ibrahim, had been sentenced to six years in prison.
They decided on a sit-down protest and started a chant of "We want justice", "Reformasi" and "Mahathir go", a reference to the unpopular Prime Minister, Dr Mahathir Mohamad.
Suddenly the police lines parted and a red water cannon roared up, followed by several riot control vehicles. Normally the sight of a police vehicle is enough to send protesters running in every direction. But this time was different.
The anger which had been building up for months over the silencing of the politician who dared - as they saw it - to challenge a crony-ridden leadership made them reckless. They charged towards the water cannon.
Tian Chua, a well-known civil rights activist, sat down in front of the truck, a symbol of defiance like the lone protester with brief case who faced a tank in China's Tiananmen Square in 1989. But two police officers pulled him away, and beat him about the head and body with sticks as a jet of liquid struck him with full force.
The cannon then sprayed a huge green cascade of water mixed with dye and pepper gas at the crowd. As the police charged, they were followed by a gang of thuggish-looking men in plain clothes, wearing bright-red cloth bands across their noses as identification and as protection against the stinging pepper spray.
They were more vicious than the uniformed police. In an alleyway, I saw two policemen holding a man as one of the plainclothes men repeatedly slapped him hard in the mouth.
The crowd reassembled at corners in the narrow streets that for a time echoed to the bangs of teargas grenades and the taunts of demonstrators as the police fought to re-establish control.
Some men in green headbands threw half-bricks and pulled hoarding into the middle of the road to set fires as shopkeepers hastily pulled down corrugated metal shutters.
At one point in heavy traffic a white car from TV3, the pro-government television channel, was attacked by people shouting "Mahathir propaganda". They smashed the windscreen and tried to pull out the terrified man and woman inside, but they got away by driving into the car in front and making a space to escape.
A young man who had been kicking the car screamed in my face: "Die Mahathir! Write that."
As the street battles surged back and forth, the lawyers for Mr Anwar were expressing their fury in cold language outside the courthouse in Merdeka (freedom) Square. "This was a vindictive sentence," said one, referring to the six-year prison term imposed by Judge Augustine Paul.
"There is no precedent in Malaysian law for the sentence not to take into account time already spent in prison," said his counsel, Mr Pawancheek Marican, adding: "It is a sad day for our country, I worry for my children."
The judge had rejected Mr Anwar's argument that he had been the victim of a political conspiracy by opponents in the government. "He was a captain of Malaysian politics. He was the number two person in the country," he said, explaining his 394-page judgment to the packed courtroom. "The offence strikes at the very core of the administration of justice."
Mr Anwar was convicted of directing police in 1997 to obtain retractions from two people who had accused him of sex crimes.
With his distraught family looking on, Mr Anwar gave vent to the anger which has been building up inside him since he was arrested last September.
"I have been dealt a judgment that stinks to high heaven," he said, as the judge looked on with a startled expression. "This is an absolute disgrace. An interpretation of corruption which is ridiculous, nauseating in fact, when one considers how in Malaysia billions of ringgit of the people's money are being squandered by its leaders to save their children and cronies.
"The charges are part of a political conspiracy to destroy me and ensure Datuk Seri Dr Mahathir Mohamad's continued hold on power at whatever cost, even if it means sacrificing whatever little is left of the judiciary's integrity."
The attorney general, he said, "had not brought an iota of evidence - indeed he has not even tried to prove - that I used my position to enrich myself or my family."
Then turning to his sobbing relatives, Mr Anwar embraced them and told them to remain calm and that the battle was far from over.
After that the day belonged to his wife, Dr Wan Azizah Wan Ismmail, the Dublin-educated eye surgeon who last week formed a new political party to fight the next general election and give the reform movement a political channel for its anger.
With the composure of a professional politician she presented herself to the mass of reporters outside after the sentence was passed. "Anwar is innocent, but has become the victim of a political conspiracy," she said.
After Mr Anwar had been driven away in a police van, Dr Azizah emerged again from a back door and made her way through the crush of photographers to the walls of the Sungai Kelang river behind the courthouse. There for 10 minutes she waved to hundreds of cheering supporters lining the opposite bank.
It was after she had gone that the confrontation began and Kuala Lumpur experienced its worst day of street violence since the early days of the crisis last year, with fears of more to come.