The fierce backlash against ExxonMobil’s climate claims has reached new heights after a damning report revealed the company mislead the public over the risk of man-made climate change for decades.

The world's largest listed oil company is already facing a looming legal threat from US states and a group of shareholders over allegations that cast doubt on the existence of man-made climate change since the 1980s despite clear evidence from its own researchers that global warming fears are valid.

Research scientists at Harvard University, which scrutinised 187 ExxonMobil climate change documents, said the company chose to doubt the reality of climate change in public, while it knew the problem was real.

ExxonMobil, like many major oil companies, has employed scientists to study climate concerns. For the past forty years the company has found that the majority of its research supports the theory that man-made carbon emissions are responsible for potentially devastating changes to the world’s climate.

Harvard’s empirical analysis found that between 1983 and the present 83pc of ExxonMobil’s peer-reviewed research papers and 80pc of its internal documents acknowledge that climate change is real and human-caused.

By contrast only 12pc of its paid-for editorial-style advertisements published in the New York Times side with this consensus, and 81pc instead expressing doubt over the reality of climate change.