The camp's location was revealed by text message and on Twitter
About 1,000 climate change protesters are making their way to Blackheath in south-east London where they plan to set up camp for a week.
Activists had been gathering in central London waiting to swoop on a site kept secret by organisers. The protesters were informed by text and Twitter.
The site was chosen because it is within view of the City and near the River Thames, organisers said.
Police said: "We are standing off and allowing people to set up camp".
They (protesters) could not have picked anywhere more middle class than Blackheath
A local resident
Ch Supt Helen Ball from the Metropolitan Police said: "We will be photographing people on arrival at the camp because it is important for us to know if there are people coming who want to cause violence and disorder.
"We will not be routinely stopping and searching everybody going into the camp and we have briefed officers carefully on searching people and what the spirit of the operation is."
'Capitalism is crisis'
The first group of activists reached the site off Shooters Hill on bicycles just after 1430 BST.
Others are arriving at the site using trains and the Underground.
A statement from organisers said: "From this heath in 1381, preacher John Ball gave what was probably the country's first speech against class oppression.
"What better place to continue the struggle for social justice and the fight against climate change?"
The group said it chose the location as it was "in clear sight of the London City skyline which symbolises the financial and corporate centres of power, and is also within the floodplains of the River Thames, which is at risk of bursting its banks as climate change escalates."
More than 20 vans and lorries were already in place and a temporary wire fence has been erected at the site by camp organisers.
Demonstrators have begun to erect tents for the seven-day camp, which has a banner carrying the words "Capitalism is crisis" at its entrance.
Lizzie Jacobs, an activist, said: "The 'swoop' is one of the most inspiring events to take part in, but it's only the beginning."
Henry Twigger, 41, who travelled to the camp from his home in Nottingham, said: "It's certainly big enough for the 3,000 people we are expecting."
''We can do sustainable living right now'' said one protester at the camp
More than 50 homes overlook the half-a-hectare sized heath which is a short distance away from Blackheath village.
A 40-year-old woman who lives nearby said: "I just hope it's going to be peaceful.
"They could not have picked anywhere more middle class than Blackheath.
"We have got a view right across the camp and I guess we will be looking at hundreds of students for the rest of the week."
The heath was the setting for the Peasant's Revoltuion, which saw thousands of protesters demonstrate against taxes more than 700 years ago.
The site hosted Jack Cade's Kentish rebellion against King Henry VI in 1450, which was followed by the Battle of Deptford Bridge in 1497 during which Cornish rebels camped at the site.
Apart from its revolutionary legacy, the heath is also the starting point for the London Marathon.
The camp will end on 2 September.
Activists had repeatedly refused to reveal the final location claiming they did not trust the police. It followed accusations the Metropolitan Police were heavy-handed in policing the G20 protests.
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