Peace protesters camping in Parliament Square have been evicted and their tents taken down.
The square has been fenced off - but Brian Haw can stay
The Greater London Authority has erected a security fence around the square saying it did not want it to become an "illegal camp site".
It said up to 28 tents have been scattered across the square in recent weeks and the majority of people in them were not protesters.
It said veteran peace protester Brian Haw would be allowed to remain.
Mr Haw has permission from the police to have a 24-hour demonstration site on the pavement of Parliament Square under the Serious Organised Crime and Police Act 2005.
The GLA said this is being respected.
The metal security fence skirts around Mr Haw's tent, where he has been living since he began his vigil in 2001.
But access to the rest of the square is being restricted by GLA officials and a small number of police officers.
Maria Gallagstegun, who has been living in a tent there for more than a year in protest at the Iraq war, said the authorities had acted without warning.
"I am outraged and I am very disappointed. They are taking away our right to demonstrate freely."
She added: "We have got no intention of going. They haven't even given me a piece of paper. No one has discussed anything with me."
Anti-war protester Claire Hollington, a 25-year-old barmaid from Bermondsey, in south-east London, said she had been camping in the square for 10 days.
She insisted the protesters had not been causing a nuisance or a hygiene problem.
"We kept ourselves to our ourselves. We kept our rubbish to ourselves.
"This is supposed to be a free democracy. We should be able to have a say over what is happening."
Miss Hollington said she was now thinking of travelling to Heathrow airport to join the climate protest camp.
In recent weeks, homeless people have been camping out in Parliament Square, according to the protesters.
One group of Bulgarians, who were packing their tents and possessions away after being evicted by officials, told BBC News they had come to Britain 10 days ago looking for work.
GLA officials say the illegal campers risk creating a public health hazard by using the site as an "open-air toilet".
But Mr Haw, who was earlier jostled by officials as he tried to prevent the removal of one of the tents, was outraged by the suggestion, saying they were as clean as anyone else protesting.
A spokesman for the mayor said: "The mayor of London respects Brian Haw's peaceful protest but others have clearly overstepped the mark.
Maria Gallagstegun has been living on the green for more than a year
"If other people wish to camp in London, there are a number of locations with the appropriate facilities such as toilets and showers.
"Parliament Square is not a campsite and no city can tolerate a situation where people are setting up tents and urinating and defecating on one of its central squares."
Solicitors representing Mr Haw recently gained a High Court victory when judges ruled that government plans to restrict his protest were unlawful.
Mr Haw, from Redditch, Worcestershire, said: "What's this idea that I can sleep here but nobody else can?
"These people have been with me 24/7. How dare they call them a public health hazard? They're the cleanest people here."
Green Party principal speaker and London mayoral candidate Sian Berry said: "Brian Haw has a right to protest.
"Yet this right is under constant attack. First his displays were confiscated, then restrictions imposed, and now his supporters are being evicted.
"The mayor and the government need to back off and restore the right to protest outside Parliament, rather than pick on Brian Haw."