Hundreds of campaigners staged protests inside and outside the UN climate talks today as security was ramped up for the arrival of world leaders for the closing days of the negotiations.
Police used tear gas and batons to disperse crowds of protesters, and arrested 230 people in clashes around the conference centre in Copenhagen.
Hundreds of people congregated around the Bella Centre in the Danish capital in attempt to hold a "people's assembly" to reclaim power on climate action from leaders, while campaigners and delegates staged a noisy walkout from the talks themselves to meet those outside.
Natalie Swift, a spokeswoman for Climate Justice Action said: "Today we are seeing thousands of people joining together to fight for climate justice.
"We need systems change to create a world which is truly just and sustainable and solve the climate crisis."
Some protesters were hit with batons while witnesses saw one man being pushed from the roof of a police van and struck by an officer.
Meanwhile, delegates from environmental group Friends of the Earth were shut out of the conference despite having the correct accreditation for the meeting.
The green group's executive director Andy Atkins said more than 50 people staged a sit-in on the floor in the entry area of the conference hall where they had been prevented from entering the centre.
He said the group's exclusion was "very worrying" as the environmental campaigners had been a strong voice for an ambitious and fair deal, and said he believed their criticism of the talks had annoyed "people in high places" who had taken action to revoke their accreditation.
Mr Atkins said the group was totally peaceful and had done nothing wrong.
He said: "It is a crisis of democracy when campaigning charities like Friends of the Earth are prevented from speaking up on behalf of communities around the globe within the talks themselves.
"We were stunned to discover that every Friends of the Earth delegate has been banned from attending these crucial talks - if this is a consequence of our role as one of the most prominent groups calling for a strong and fair agreement, this is even more disturbing."
He added that the Copenhagen conference was "fast becoming an international shambles".
The protests forced Gordon Brown to abandon a planned meeting at his city centre hotel after security advisers told him to stay at the conference centre "for convenience and safety", Downing Street said.
The Prime Minister, who was at the talks venue to listen to proposals being put forward by the African Union, decided to stay and carry out the planned briefing by telephone.