A central plank of David Cameron's bid to modernise the Conservatives has come under fire with two prominent Tories questioning aspects of the party's green re-brand.
By Hugh Levinson
Producer, Radio 4's Analysis
Euro MP Caroline Jackson has attacked the Quality of Life review group, headed by ex-Cabinet minister John Gummer, which is briefed to develop new ideas to fulfil David Cameron's promise of putting sustainability at the heart of Conservative policy.
She says she suspects the group's purpose is partly "cosmetic" and that the party's environmental agenda will be subverted by Mr Cameron's policy on Europe.
But a spokesman for the Conservative Party said: "The quality of life review is one of the six major policy reviews set up by David Cameron and reflects our belief that the environment has for too long been treated by politicians as an afterthought.
"That has to change, and our commitment to tackling climate change and preserving and enhancing our quality of life will be fundamental to the policies that we put forward at the next election."
In an interview for BBC Radio 4's Analysis programme, Dr Jackson also questioned the party's commitment to environmentalism. "I think from the point of view of the Conservative party pursuing the green line is all talk and no action at the moment," she told the programme.
"It's part of the current process in the Conservative party of giving green issues prominence and taking up some pretty strange positions on some things I think.
"When push comes to shove in the general election I suspect we will roll back from some of this."
The programme also uncovered deep divisions over the science of climate change.
Peter Ainsworth, the shadow environment secretary, described global warming
as "the biggest threat we face."
He said he agreed with Sir David King, the government's chief scientific advisor, that climate change was a bigger danger than terrorism, adding that global warming "has killed more people already than international terrorism."
A central theme of Mr Cameron's thinking is under fire
This contrasted sharply with the views of John Redwood, who is leading the party's review into competitiveness. He said it wasn't clear that human activity was changing the climate.
"There's quite a good literature which says that if you have a sudden outbreak of massive volcanic activity it would completely swamp anything mankind was doing," he said.
"I'm told by scientists who know that sunspot change on the sun could do far more than humankind. So there are all these uncertainties."
Environmental campaigners told the programme the Conservatives would have to resolve these tensions if they wanted convincing green credentials.
"I think the Conservative party face a challenge which could be as significant as the debate they've had internally over Europe," said Andrew Simms of the New Economics Foundation.
He said the party was split between a conservationist camp and a free market camp. "Those camps are actually on either side of a very big river," Mr Simms said.
And if David Cameron tries to sleep in both, "he's going to get wet," he added.
Meanwhile Dr Jackson criticised the Tory leader's plan to withdraw the party's MEPs from their alliance with the centre-right European People's Party, the largest group in the European Parliament.
Dr Jackson, who chaired the European Parliament's environment committee for five years, says this will leave Tory MEPs powerless.
She asked how far the review group will be able to operate "without being able to get in touch with the people who are actually pulling the strings in Europe."
"If you are threatening to leave the largest political group in Europe, whose members have the chance of influencing European environmental legislation in a major way then it is a disaster that you can't go and talk to them."
Analysis will be broadcast at 2030 BST on 6 April and repeated at 2130 BST on 9 April on BBC Radio 4.