Two of the protesters were injured in hospital, having been knocked over by police vans, while dozens of others were being treated in casualty wards for head wounds and cuts. Despite the remnants of the crowd partying in Trafalgar Square throughout the evening, the self-proclaimed "Carnival Against Capitalism" had well and truly turned sour.
The idea behind the loosely organised demonstration had been to highlight the supposed evil of the multi-national money men and their impact on the debts of Third World. But however well-meaning, it inevitably attracted a "rent-a-mob" of about 4,000 all-purpose protesters, from environmentalists to animal rights activists and snarling skinheads intent of some serious confrontation.
"We've come to fight capitalism, it's our future and at the moment it's one of decay. We want to take part in reclaiming our lives. We are not just money making machines," said a 17-year-old female member of the group Reclaim the Streets, among the main instigators of the action.
Early acts of defiance were innocent enough, with eight demonstrators going into Lloyds Bank in Cheapside and chaining themselves to fixtures with bicycle locks. Six more entered the nearby NatWest bank, but left without trouble after police were called. Two others were removed from Tower Bridge after they tried to climb the structure, and demonstrations were also held outside the Bank of England on Threadneedle Street.
Optimism remained high that trouble could be avoided, and the formidable show of force by the City of London Police, with reinforcements from the Metropolitan Police, seeming happy to watch from the sidelines.
John Curtin, handing out leaflets outside a McDonald's restaurant, agreed with the tactics. "I was protesting with Stop the City in the 1980s. There were running battles with police in the streets. Today they are being very fluffy. As long as they keep their truncheons away, they'll be no trouble."
The illusion was shattered in mid afternoon when the protesters broke up into four groups and police came under attack from stones and bottles.
"Missiles are being thrown at police and police vehicles have been damaged," said a police spokesman at the time. "They are throwing stuff from building sites - bricks, concrete blocks and other debris. All four groups have started to use unprovoked gratuitous violence against the police."
At about 4.30pm a woman went under the wheels of a police van on London Wall as it tried to reverse out of an attack, and the trouble escalated violently. Screaming demonstrators climbed on to the roofs on other police vehicles and the missiles kept raining in, to be met with baton charges and police horses. The truncheons were out in earnest.
Symbols of "morally and politically incorrect" institutions then came under direct attack - a Dutch bank had glass panels smashed with scaffolding poles, a Mercedes Benz showroom was wrecked in similar fashion and a McDonald's restaurant suffered damage inside and out. Much of the damage was concentrated in a quarter-mile stretch of Upper Thames Street.
At the Liffe futures and options exchange on Cannon Street, protesters met their match. After bursting in, wrecking the atrium and trying to get onto the trading floor they were confronted by groups of "barrow boy" traders, furious at having their lucrative activity disrupted.
"The locals battled with the demonstrators right on the escalators and stopped them coming upstairs. They were really heroic," said James Shelden, chief executive of brokers GNI.
As the fighting went on, the "walking wounded" started to arrive at local hospitals. A total of 46 people needed treatment. The woman who was knocked over was treated for concussion and a leg injury at the Royal London Hospital, along with a man who also went under the wheels of a police van. Neither was said to be in a serious condition.
As the crowds dispersed towards the West End, all the City Tube stations were closed to stop any further protesters arriving. Office workers were stranded. Most took the opportunity to go for a drink in bulging bars and pubs, watching as the clean-up operation began.
One former employee said: "I used to work there and they were a bunch of capitalist bankers. So I fully sympathise with what they are doing." Others had more sympathy for the police trying to fend off yet another attack.
One City worker said: "What is their cause?" while another woman added: "If they think they are going to put us off capitalism like this they are going about it the wrong way."Reuse content