Demonstrations have taken place around the UK to urge action on climate change ahead of the Copenhagen summit.
Organisers Stop Climate Chaos want world leaders to reach a tough new deal on cutting emissions.
In London, police originally said about 20,000 people had taken part – but did not contradict claims by the organisers that the actual figure was over 40,000.
Gordon Brown praised the protesters for "propelling" leaders to reach the "first world climate change agreement".
The prime minister, who met some of the demonstrators in Downing Street, said it was essential that a deal be reached in Copenhagen and leaders had to be "ambitious".
Mr Brown said he and the "vast majority of people" were convinced by the scientific evidence for man-made global warming.
The above is from the BBC.CO.UK/NEWS website. Compare the attitude of the British Prime Minister, who is engaging with protesters and who is using the strength of public feeling in the UK to galvanise world leaders into action at Copenhagen. Compare this to the attitude of the Australian government, who wont even agree to meet with us to allow us to deliver the results of our petition.
