The Charity Commission has concluded that an education charity chaired by the former Chancellor Lord Lawson "promoted a particular position on global warming".
The Global Warming Policy Foundation was registered with the commission in 2009 with objects of advancing education and promoting research into the science of global warming and global warming policy.
An operational compliance report, published by the regulator today, says it became involved after concerns were raised that the charity was promoting views that were of a political rather than an educational nature.
The commission said that it examined the work of the charity, including its website, blog and publications, and had "extensive and constructive engagement" with the charity, analysing its work against the legal framework for educational charities.
Educational charities must demonstrate balance and neutrality in their activities, the regulator’s report says.
"The high media profile of the charity and the concerns raised as to its political nature created a potential risk to the integrity of the sector that required the commission to get involved to ensure the charity operates for the public benefit and within the permitted framework in relation to campaigning and political activities," it says.
The report says that the charity’s trustees explained that it aimed to "restore balance and trust to a debate that it considered chronically one-sided".
It says: "The trustees considered that by also publishing counter-arguments, amongst others, it was advancing education and that its website acted as an educational or public resource."
The charity told the commission that there was a wide divergence of opinions among members of its advisory council and that it did not support any particular view.
But the commission’s report says: "The commission found that, taken as a whole, it was difficult not to form the conclusion that the publications and postings on the charity’s website promoted a particular position on global warming.
"The website could not be regarded as a comprehensive and structured educational resource sufficient to demonstrate public benefit. In areas of controversy, education requires balance and neutrality with sufficient weight given to competing arguments. The promotion of a particular view or position would not equate to education."
The report says that the charity this month launched a non-charitable organisation to act as a campaigning body to promote opinions and policy change, leaving the charity to focus on its educational objects.