By Mario Cacciottolo
It was a case of two worlds gently bumping, rather than colliding, into one another on the steps of the Bank of England.
Smartly-dressed men and women inched their way past people who looked as though they were off to a festival, equipped with rucksacks, mats and sleeping bags.
But there was something more serious on the agenda for those sitting patiently in the sun - they were waiting for the location of Climate Camp 2009 to be revealed.
The Bank of England was one of six spots around London where those intending to join the camp had been told to wait until a text message from the organisers would tell them where to "swoop".
Campers set about pitching tents at the start of the week-long protest
Among those waiting was 23-year-old Frank, from east London, who said he planned to stay at the camp "for as much as I can" and talked of humanity "committing suicide".
After several hours, and a quick bingo-type game to keep the crowd of about 200 people occupied, an announcement was made to head for the Cutty Sark stop on the Docklands Light Railway.
Part way through the journey, as the train emerged from underground, mobiles began to beep and vibrate and the location was revealed as Hare and Billet Road in Blackheath.
One camper on the train helpfully mentioned the area was linked with Wat Tyler and his army, who marched on London in protest at the first poll tax in 1381 and stationed the men in Blackheath.
And so it was that a large, flat patch of Blackheath grass, beneath an increasingly ominous-looking sky, was "swooped upon" by the climate campers.
The site is known as Dartmouth Field.
One of the first to arrive was Max, 26, from south London - among a group of cyclists who met underneath Waterloo Bridge.
He confessed to not being terribly well prepared for the trip, and said he hoped to return to actually stay over the weekend.
Kate Salter is looking to learn more about sustainable living
"The best we can hope for is that it raises enough attention so that people become interested and find out what climate change is and what Climate Camp are doing about it."
Kate Salter, 29, came up from Brighton with her three-year-old daughter Jem.
"I'm quite interested in the workshops they are running, which will teach you about sustainable living and how to help the environment."
Around the site campaigners pitched tents, as others arrived with small vans and unloaded creature comforts including a sofa. One pile of items even has two toilet seats on the top.
The skyline of the financial company buildings in the Docklands can be seen in the background.
It was hard to spot any police - a couple of vans drove past slowly, but nothing more.
Despite this, a fence was swiftly erected, which will apparently be guarded around the clock by the campaigners for the week-long duration of the camp.
Tripods made up of metal scaffolding poles also sprung up, each with someone sitting on top.
Some said these were to stop police entering the field in vehicles - a kind of human shield.
Guy's job is to construct some toilets
And in one section of the field, there was an impressive amount of wood lying on the grass.
Standing among it, with a plan to transform it into toilets, was 22-year-old student Guy.
"I hope the camp will help people realise that we can't have more climate change dialogue now," he said.
"We've got to the point where we have to stop talking about it and must do something about it instead."
From a van, mattresses are unloaded for the "wellbeing space", which according to one woman was where people can find "comfort, relaxation, and tea".
In the distance, in a stroke of opportunism, an ice-cream van parked at the kerb, looking to benefit from the 800 to 1,000 people at the site by now.
Standing on the edge of the field, local resident Julian Crispin, 74, who lives five minutes away, was walking his dog, Percy.
"I just wondered whether it suits their purpose to be out here rather than in central London," he said.
"I'm supportive of their cause but I hope there's no permanent damage to the heath and that they take all their rubbish away with them.
"I also hope they don't keep the neighbours up all night, playing their bongo drums and such like."
A short while later, the campers gathered round, and announcements were made over a patchy loudspeaker system.
"Can I have a whoop for the swoop?" cried a young woman, and the crowd responded with gusto.
Climate Camp 2009 has begun with high hopes and dreams of a better world. What it will actually achieve remains to be seen.