Tens of thousands of demonstrators from trade unions and environmental and anti-capitalism groups marched through London yesterday, starting a series of mass protests ahead of the G20 summit.
Police estimated the crowd at up to 35,000 but there was no sign of the feared violence as the placard-waving crowd snaked along the six-kilometre route to Hyde Park.
An alliance of more than 150 unions, charities and environment groups joined the march to demand action to save jobs, create a low-carbon economy and impose stricter controls on the finance sector.
World leaders, including US President Barack Obama on his first visit to Europe since he took office, will meet in London on Thursday for the Group of 20 summit amid the deepest global recession since the 1930s.
Organisers of the 'Put People First' march for 'jobs, justice and climate' had rejected as 'smears' claims in police briefings that the march could be hijacked by anarchists bent on violence.
The general secretary of the Trades Union Congress (TUC), Brendan Barber, said the demonstration had a clear message for the presidents and prime ministers heading to London.
"Never before has such a wide coalition come together with such a clear message for world leaders," he said.
"The old ideas of unregulated free markets do not work, and have brought the world's economy to near-collapse, failed to fight poverty and have done far too little to move to a low-carbon economy."
One protester, Chris Pounds, 45, a health worker from Northampton in central England, told AFP that the groups in the march were united in their belief that global leaders had "made a real mess" of the economy.
"We have got to start again to find a new way of living because over the last year we've seen that our so-called leaders don't know what they are doing.
"I don't care what happens at the G20 summit - we don't need their help," he said.
The protesters set off accompanied by brass bands and blaring rock music and waving banners with slogans such as 'We won't pay for the crisis', 'Plan it with the planet in mind' and 'Capitalism always leads to death'.
One anti-capitalism group marched behind the head of a devil plastered with dollar bills. Later in the day, campaigners were set to target companies and buildings that fail to switch off their lights, promising to force their way into 'offending' tower blocks and offices.
That action is part of the global Earth Hour initiative which seeks to urge people to turn off the lights for an hour.
British Prime Minister Gordon Brown hopes the G20 meeting will help set the world on the road to recovery from the deepest recession since the 1930s.
Actor Tony Robinson, a star of the cult TV series Blackadder, who attended the march, said the G20 needed to demonstrate that politics should be about people not profit.
"I certainly do think that if we have a big strong promise on the regulation of international capital coming out of that meeting then that would be a huge step forward because we can't get anywhere until all this dosh (cash) stops swirling around the world," he told BBC television.
More protests are planned in London in the days leading up to the summit.