Campaigners in London and Edinburgh have joined a global protest taking place in 32 countries in a mass call for action over climate change.
Concern has been expressed globally at emissions
Thousands marched through London in a protest which ended at the US embassy.
Dozens of protesters marched to the Scottish Parliament in Edinburgh via the Royal Mile.
The marches coincide with UN climate talks in Canada attended by Environment Secretary Margaret Beckett and Environment Minister Elliott Morley.
The protests were organised by the Campaign Against Climate Change.
Campaigners in London went past Downing Street, and a letter demanding more Government commitment to emission reductions was handed in to No 10.
Former environment minister Michael Meacher said "I certainly think government will be watching this very carefully. And I think it will have an increasing impact on public opinion.
"I'd like to think we may be doing our little bit to add to the cacophony around the world in our anger at President Bush still distancing himself from what the rest of us throughout the world believe is absolutely necessary."
'We are watching'
The Edinburgh march began at East Market Street at 1100 GMT and finished at the Scottish Parliament about an hour later.
Green MSP Mark Ballard, who addressed the protesters, said: "The eyes of future generations are on Montreal.
"Across the world, more than 30 protests will make sure that our leaders know that we are watching them too."
He said: "Tony Blair has caved in to the US approach of abandoning targets on reducing emissions in favour of complacency."
The Montreal talks follow on from the Kyoto Protocol, which was signed in 1997 and called for 30% cuts by 2020.
Mr Meacher earlier told BBC Radio 4's Today programme further reductions in greenhouse gas emissions - widely thought to contribute to rising temperatures - are vital.
"We need now to aim for more. That is what climate change is telling us. We need to say minus 25% by 2025.
"I do think it's important that we don't kowtow to US demands to scrap Kyoto. Because whatever concession we make to the Bush administration we will get nothing in return, just like we got nothing in return over Iraq."
He said the Bush administration "will never sign up to any meaningful agreement on reducing greenhouse gas emissions".
Mr Meacher said it was more important to sign up developing countries such as China and India to climate change protocols.
He said industrialised countries need to be seen to make cuts so other countries would follow.