By Richard Black
Environment correspondent, BBC News website
The BBC has scrapped plans for Planet Relief, a TV special on climate change.
Ricky Gervais had reportedly expressed interest in presenting
The decision comes after executives said it was not the BBC's job to lead opinion on climate change.
Celebrities such as Ricky Gervais were said to be interested in presenting the show, which would have involved viewers in a mass "switch-off" to save energy.
The BBC says it cut the special because audiences prefer factual output on climate change. Environmentalists slammed the decision as "cowardice".
"This decision shows a real poverty of understanding among senior BBC executives about the gravity of the situation we face," said activist and writer Mark Lynas.
"The only reason why this became an issue is that there is a small but vociferous group of climate 'sceptics' lobbying against taking action, so the BBC is behaving like a coward and refusing to take a more consistent stance."
The Planet Relief concept originated about 18 months ago, and was tentatively scheduled for broadcast in January 2008. It was seen as a climate change counterpart to programmes such as Live8, which sought to raise awareness of global poverty.
But against the backdrop of intense internal debates about impartiality, senior news editors expressed misgivings that Planet Relief was too "campaigning" in nature and would have left the Corporation open to the charge of bias.
"It is absolutely not the BBC's job to save the planet," warned Newsnight editor Peter Barron at the Edinburgh Festival last month.
Head of TV news Peter Horrocks, writing in the BBC News website's editors' blog, commented: "It is not the BBC's job to lead opinion or proselytise on this or any other subject."
A number of right-wing commentators such as the Daily Mail's Keith Waterhouse also criticised the idea.
But a BBC spokeswoman said the cancellation was not due to concerns over impartiality.
"BBC One aims to bring a mass audience to contemporary and relevant issues," she said, "and this includes the topic of climate change.
"Our audiences tell us they are most receptive to documentary or factual style programming as a means of learning about the issues surrounding this subject, and as part of this learning we have made the decision not to proceed with the Planet Relief event.
Planet Relief was modelled on anti-poverty events such as Live8
"Instead we will focus our energies on a range of factual programmes on the important and complex subject of climate change. This decision was not made in light of the recent debate around impartiality."
Is is believed that poor ratings in the UK and elsewhere for July's Live Earth concert may have confirmed the internal belief that the public do not like being "lectured to" on climate change.
However, executives associated with Planet Relief, developed under the aegis of BBC Comedy, said the aim was not to campaign but to "raise consciousness" about the science of climate change, and to offer them the opportunity to take part in a mass temporary "switch-off" of electrical equipment.
Negotiating this with the National Grid had taken over a year, as engineers feared the switch-off might overload parts of the network.
Many blogs run by climate sceptics groups regularly accuse the BBC of bias and of ignoring evidence which runs against the idea that elevated levels of greenhouse gases from fossil fuel burning and land clearance are raising temperatures around the world.