A TELEVISION advert for a "green" car driven by celebrities including Leonardo di Caprio has been ditched, after watchdogs criticised its environmental claims as misleading.
In UK commercials, Toyota boasted that their Prius model, a favourite with planet-saving stars, used "one tonne less per year" than others cars.
But an investigation by broadcast regulators found these figures were not true when comparing the 1.5-litre Prius against cars with a similar-sized engine and only matched half of those with a 1.8-litre engine.
The Japanese car-maker was found guilty of breaching rules on using evidence, environmental claims, comparisons with other models and misleading advertising, said the Advertising Standards Authority (ASA).
The Prius has long boasted that its hybrid electric-petrol engine belches out less carbon dioxide than traditional petrol or diesel engines.
This has led to a rush of celebrities buying it to emphasise their environmentally aware credentials, including the singer Donny Osmond and the creator of Seinfeld, Larry David. Harrison Ford was chauffeured to an Oscar ceremony in the "green" machine.
But television adverts in the UK could not justify the claims, after regulators examined how the comparisons were made. The Prius pumps out 104g of for every kilometre travelled, according to official industry figures.
Toyota compared this with the average 172g of /kg for all new cars and then multiplied the difference of 68g/km by 12,425 miles, which is claimed to be the average domestic mileage for a motorist. But the ASA discovered that this figure is for the average US motorist, not the average British driver, who drives only around 8,327 miles a year - up to a third less.
Toyota told the ASA: "[We] qualified the claim by stating 'up to' one tonne less, to make clear that the emissions saved would not always be as much as one tonne."
The company also claimed the ad was passed by an independent consultant, "who had advised it was suitable to show that the Toyota Prius emitted significantly less than other cars".
The ASA upheld a viewer's complaint about the green claims made in the ad and ruled that it could not be shown again. The ruling said: "While the average annual distance driven by private cars in the US was 12,425 miles, the average for the UK was 8,327 miles.
"Toyota had qualified the claim by stating 'up to one tonne less per year' and the Prius emitted significantly less than some other cars with greater engine capacity.
"But we did not consider their evidence demonstrated that it emitted one tonne less than equivalent vehicles with diesel engines, or took into account the average annual distance driven by private cars in the UK."