Gordon Brown will insist today that Britain must be a world leader in the fight against climate change - hinting that more ambitious reductions in greenhouse gas emissions may be necessary.
In his first major speech on the environment since becoming Prime Minister, he will underscore the need to act immediately to combat global warming.
Despite claims that he has been under pressure to curb commitments to reducing carbon emissions Mr Brown will stress he is looking at the possibility of making them even tougher in the UK.
