Best in Class

Best in class:
Audi A8 3.0 TDI - 174g/km

Best of the rest:
BMW 730 D - 178g/km
Jaguar XJ6 3.0 D - 184g/km
Audi A8 2.8 - 199g/km
Mercedes S 350 CDI Blueefficiency - 199g/km
Lexus LS 600H - 219g/km

Luxury cars produce decidedly more CO2 than executive cars, and often offer little more in the way of space, even though they are better equipped. The new Audi A8 3.0 TDI has just pipped the BMW 7 Series to the top spot. Just behind is Jaguar, whose lightweight new XJ is also exceptionally efficient. Audi's FSI engine is still up there though with CO2 emissions of 199g/km - the only petrol-engined saloon in any segment to appear in the list of lowest-emitting vehicles. This is thanks to clever aluminium construction, used in conjunction with direct injection and variable valve technology, to boost economy. The Lexus LS 600h has been left some way behind, despite its hybrid drivetrain.