Europe's largest car maker, Volkswagen, is accused of exaggerating its green record and resisting attempts to make popular models such as the market-leading Golf more fuel efficient.
The VW Group has made less progress on fuel efficiency than rivals such as BMW and Toyota and is actively seeking to thwart EU plans to reduce climate-change emissions by 2020.
Volkswagen, which makes Audi, Seat, Skoda and Bentley cars among others, has also lobbied against environmental legislation on vehicle fuel efficiency and lower emissions, Greenpeace claims. And it opposes the efforts for tougher EU emissions cuts of 30% by 2020, despite support by many other major companies for the move.
The report also said that the car giant had failed to cut petrol consumption in its cars as quickly as other manufacturers, and has failed to make technology it has developed for highly fuel-efficient vehicles standard across the fleet. Just 6% of the Volkswagen Group's global sales in 2010 were of its most efficient models, the report claims.
Greenpeace's Emma Gibson, speaking at the launch of the campaign, said: "Volkswagen has spent millions on its new advert, using children and Star Wars iconography to persuade the public that it's a responsible company.
"It was a stunningly successful advert, so VW can hardly complain if we now turn its own tactics back on the company to shine a light on its poor environmental record.