Parliament Square anti-war protester Brian Haw arrested
Police with sniffer dogs searched the tents in Parliament Square
Parliament Square protester Brian Haw has been arrested for obstructing police during searches of tents on the green.
Anti-war campaigner Mr Haw, who has been camping there since 2001, was held as police searched the "peace camp".
Another protester Barbara Tucker, who has also been camping outside the Houses of Parliament, was arrested.
Mayor Boris Johnson will be applying to the High Court to remove the activists from the camp, his spokesman said.
The green is owned by the Greater London Authority (GLA), but the spokesman said the mayor or the GLA had nothing to do with the police searches and arrests.
Meanwhile, human rights' group Liberty has criticised the police action against the protesters.
A Metropolitan Police spokesman confirmed that two people had been arrested in Parliament Square at about 0800 BST for obstructing police.
Police with sniffer dogs searched the collection of tents opposite the Houses of Parliament before the Queen arrived at the state opening of Parliament.
As she was arrested Ms Tucker was heard saying on BBC London 94.9: "You can't arrest him [Mr Haw], you don't have a search order."
Phoenix, an environmental activist who has been living in the camp, witnessed the arrests.
He said: "I didn't like the way he was held in a stress position and was taken off.
"He was carried off by four officers with his whole body weight on his forward shoulders...he wanted his crutches."
Mr Haw, of Redditch, Worcestershire, set up his camp in protest against sanctions on Iraq and then over the war.
In 2007, he won a legal battle to remain in place due to a drafting error in a new law banning unauthorised protests in Westminster.
Since 1 May several other tents and flags have cropped up on the green, which has been dubbed Democracy Village by campaigners, who include anti-war demonstrators, climate change activists, communists and anarchists, as well as some homeless people.
The "Democracy Village" was set up on 1 May
A spokesman for the London mayor's office said: "The mayor respects the right to demonstrate, however the scale and impact of the protest is now doing considerable damage to the square and preventing its peaceful use by other Londoners - including those who may wish to have an authorised protest," he said.
"As a result he has given GLA officers the authority to apply to the High Court to begin legal proceedings for trespass."
Councillor Colin Barrow, Leader of Westminster City Council, backed the legal action.
"We felt that the hijacking of Parliament Square, one of London's historic public spaces, needed to be brought to an end," he said.
Liberty director Shami Chakrabarti said about the police action: "We are very sad to see that on a day that is supposed to celebrate British democracy, peaceful dissent is also shut down.
"The new coalition government has promised to restore the right to non-violent protest. Attempts to clear Parliament Square are not the most promising."
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