As well as anti-globalisation protests, climate change campaigners are also out in force today. Our correspondent Jerome Taylor is with them:
Environmental activists weren't joking when they said they'd "swoop" on the City to set up their climate camp. At exactly 12.30pm they arrived en masse, banging drums, dancing to carnival music and turning the usually staid and grey streets of the Square Mile into a veritable carnival of colour and dance.
At a very rough guess, there must be at least 1,000 protesters currently outside the carbon exchange (ECX) on Bishopsgate. There is a strong police presence but the authorities appear to have accepted that there was very little they could have done to stop the camp and have let it go ahead without a fight.
Outside Deutche Bank, as bemused employees peered through the glass of their besieged office, a group of women were dancing to drum beats and two activists dressed as mermaids are holding signs saying "Sea Level 2050". The pavements are already littered with chalk graffiti and environmental slogans whilst the main road has been turned into a campsite more reminiscent of a music festival rather than the heart of London's financial district. The smell of incense (and no doubt a few other herbal scents) wafts through the air.
Activists say they are pleasantly surprised that the police let the camp go ahead.
Lucy Jones, a 25-year-old demonstrator from the south west who has taken part in previous climate camps at Heathrow and Kingsnorth said: "I'm very relieved the police didn't try to stop us. At Kingsnorth the policing was extremely heavy, they stopped and searched everyone and were very unpleasant. They seem to have learned this time around that confrontation is not the way forward."
Others accused the police of over hyping the potential for violent conflict. "For the past week the police have been suggesting that we'll be violent but our movement only demonstrates peacefully," said activist Tom Lewis. "I think they they played up the threat of violence to protect themselves from criticism i it occurred."
For the next two days now protesters will camp out on Bishopsgate, complete with their compost toilets, vegan canteens and environmental workshops where they will preach the message that carbon exchange does nothing to alleviate the dangers of rising globa carbon emissions.