In a critical sign that environmentalists have lost faith in Mr Blair, WWF, Greenpeace and Friends of the Earth separately rounded on the Prime Minister accusing him of undermining efforts to tackle the growth of greenhouse gases. Greenpeace activists underlined the point by dumping several tons of coal in Downing Street in protest at the increased use of the fuel in Britain despite a commitment to reducing carbon emissions.WWF also accused Britain of caving in to pressure from the United States and Germany by "critically weakening and delaying" new legislation to outlaw harmful man-made chemicals, due to be debated by MEPs this week.
Green campaigners feel betrayed after Mr Blair made the environment a centrepiece of Britain's presidencies of the G8 and EU, both of which expire at the end of the year. They say the Prime Minister has actually undermined hard-fought gains, particularly on the Kyoto protocol, by questioning the need for binding targets on reducing emissions and by suggesting they might be incompatible with economic success. Phase two of the treaty's negotiations is due to begin in Montreal later this month.
Andrew Lee of WWF said: "Despite the huge difference in historic rhetoric on the key issues of climate change and the control of hazardous chemicals, the actual negotiating position of the Prime Minister becomes daily less discernible from that of US President George W Bush.
"It is becoming clear that all the talking up has been aimed more at trying to please environmentally concerned voters and green organisations than demonstrating the will to actually use leadership in tough negotiations."
Campaigners are particularly alarmed that Mr Blair's speech to the G8 earlier this month has been interpreted in the US as open support for Mr Bush, who has refused to sign up to Kyoto. Stephen Tindale, a former adviser to Labour and now executive director of Greenpeace said: "Mr Blair is subtly back-sliding on his commitments and falling into the embrace of climate change sceptics - notably on the right of the Republican Party - who are welcoming their new ally with open arms."
Tony Juniper, director of Friends of the Earth, said the Prime Minister's credibility on climate change was "evaporating fast". He said: "A fundamental review of all government policies is desperately needed if the UK is to meet its targets for cutting carbon dioxide."
The Government has been accused of delaying its plan for hitting its target of reducing emissions by 20 per cent on 1990 levels by 2010. The latest estimate is that the UK will achieve a figure of 13 per cent.
The shadow Environment Secretary, Oliver Letwin, said: "The Government's record to date on achieving carbon reduction has unfortunately not lived up to its rhetoric - and there are now worrying signs that the Prime Minister's resolve is weakening."
The Government's chief scientific adviser, Professor Sir David King, defended Mr Blair, calling the criticism "grossly unfair". Among the Government's achievements, he said, was the prospect of 12 states in the US adopting emissions trading. All five states in Australia are committed to reducing emissions, he added.
"The message needs to be got across that this isn't at the expense of growing economies. I don't think any country is going to manage a process where the suspicion is that they will need to reduce their GDP growth," said Sir David.