General Motors, the world's largest carmaker, has confirmed that it is pulling funding from the Heartland Institute, an ultra-conservative thinktank known for its scepticism about climate change.

The decision by the GM Foundation to halt its support for Heartland after 20 years underlines the new image the carmaker is seeking to project as part of its social responsibility programme. In the past GM has itself been associated with efforts to discredit climate change science, but in recent years it has been investing heavily in green technologies and cars including the electric/petrol hybrid, the Chevy Volt.

In a statement, GM said that it now runs its business "as if climate change is real and believe we have a role to play in developing new cars, trucks and technologies that can make a difference".