Police scuffled with scores of anti-G8 demonstrators in central London and surrounded a building where protest organisers were meeting on Tuesday before a summit of world leaders in Britain next week.
Isolated scuffles broke out when police moved in to arrest individuals as a main group of around 30 to 50 activists, mostly dressed in black, banged on drums and blew whistles as they ran through the capital.
The demonstrators were staging a “Carnival Against Capitalism” across London to start a week of action before Britain hosts the meeting of the Group of Eight leading industrialised nations at a golf resort in Northern Ireland.
Some of the world’s biggest hedge funds, private equity firms and banks have warned their staff to take precautions in the event of disruption after similar protests in recent years led to violent clashes with police, vandalism and buildings being temporarily occupied.
Police descended on premises just off Regent Street, one of London’s best known shopping areas, in the fashionable Soho district, where the StopG8 group had been meeting before the demonstration.
More than 100 officers in riot uniforms formed a cordon, trapping the gathering protesters in a tight area around Beak Street as police helicopters hovered above and reinforcements waited in vans.
London’s Metropolitan Police said it had a search warrant for the address.
“People inside the property…are free to leave but will be searched,” the police said on Twitter.
Activists, some with their faces covered, waved black, green and red flags as they marched through Oxford Street. They carried banners saying “No borders, no prisons, no capitalism” and “One Common Struggle”.
There were skirmishes around Oxford Street, with television footage showing police dragging one protester to the ground.
“Humanity is spiralling towards extinction,” said one protester, who identified himself only as Silvester. “We are facing the biggest crisis ever. We oppose governments and corporations. And the G8 is emblematic of all that.”
Last month, StopG8 issued a map of 100 potential targets for people to “show their anger”, identifying offices of financial organisations such as banks, hedge funds, defence manufacturer BAE Systems and mining and energy companies including ArcelorMittal and BP.
Recent demonstrations against the British government’s austerity measures have been marred by rioting anarchists, while many Britons angered by bank bailouts and bonuses during tough economic times blame the financial sector.
In 2009, police made more than 100 arrests after protests by tens of thousands of people to coincide with a G20 economic summit in London turned violent.