The Coalition Government's claim to be the "greenest government ever" has come under fresh scrutiny from politicians and environmental groups who accuse Britain of undermining a Europe-wide forecourt ban on one of the most climate-polluting fuels.
Britain is one of just two major European nations opposing efforts to prohibit sales of petrol and diesel obtained from the Canadian tar sands.
Canada's tar sands contain the world's largest oil reserves after Saudi Arabia, but extracting the oil can release up to three times more greenhouse gases.
It is estimated the sands hold about 175 billion barrels of recoverable oil, but the trapped crude is in such thick form that large amounts of energy and water are needed to refine it. The development of Canada's tar sands has led to a push by oil companies to set up similar ventures in Russia and Congo.
Now the Transport minister, Norman Baker, has suggested that the British Government will not support an EU push to include tar sands in its new fuel directive this year, committing members to reducing carbon emissions.
The directive sets a legally binding six per cent greenhouse gas reduction target for Europe's transport fuels by 2020. Campaigners say that the inclusion of tar sand fuel emissions – which are at least 23 per cent greater than conventional oil emissions – would in effect ban the carbon-intensive crude oil from entering the European Union.
To date, the UK and the Netherlands, two nations with the strongest connections to oil giants BP and Shell, are the only two states wishing to remove reference to tar sands from the draft proposal, according to the coalition of green groups working on the directive.
Paul Monaghan, head of sustainability and social goals at The Co-operative, said: "Failure to address tar sands emissions would undermine the whole objective of this landmark climate change legislation. There is no reasonable rationale not to include the tar sands in the directive – it is clear the Government have swallowed Canada's line that we are just taking about another source of conventional crude oil.
"These reports of lower emissions from Canada just don't stand up to scientific scrutiny, while the 23 per cent figure has been approved by the European Commission's independent study."
According to Mr Monoghan, "exploiting Canada's tar sands reserves alone would be sufficient to take the world to the brink of runaway climate change".
In a letter to The Co-operative on 5 May, Mr Baker said the UK is opposed to the inclusion of tar sands in the directive until all crude oil sources with above-average emissions are also included. A spokesman for the Department of Transport said: "The Government is committed to reducing greenhouse gas emissions from transport fuels. Be in no doubt, we want to address the higher emissions of fuel derived from all heavy crudes, not just single out one particular source."
Politicians and campaigners called this a "simple stalling tactic", which could take years to complete. MEP Linda McAvan, who sits on the European Parliament's Environment Committee, said: "I know that the latest lobbying ploy for those who are opposed to accurate labelling of tar sands is to suggest a further delay for further research on different types of conventional oil. I find it unacceptable that a country which has not even tried to meet their Kyoto emission reduction target should be lobbying to water down the EU's environmental legislation."
Charlie Kronick, a climate adviser at Greenpeace, said the power of large companies like BP should not be "underestimated" when it comes to the Government's decision-making. "The UK is measuring up environmental interests and business interests and, as ever, when a nation is struggling to come out of a recession, the business case gets a strong push," he said.