Nissan

Without stop-start technology or a hybrid model, Nissan trails its Honda and Toyota rivals for eco-friendly offerings in the UK.

In the past, the firm has relied on sales of thirsty four-wheel-drive cars, such as the Pathfinder. But earlier this year, bosses kick-started Nissan’s green ambitions with the new Pure Drive sub-brand.

This tag is added to models that emit less than 140g/km of CO2. So far, the cleanest addition to this range is the new Pixo city car.

Developed in partnership with Suzuki, the 1.0-litre three-cylinder machine puts out only 103g/km and returns 64.2mpg.

Elsewhere in the line-up, you’ll find the 1.5-litre dCi-engined Note mini-MPV and Micra supermini, which emit 119g/km and 120g/km respectively.

Pick the same powerplant in the versatile Qashqai crossover, and CO2 output jumps up to 149g/km, meaning a £125 annual tax bill.

While keen drivers will love the GT-R supercar and 370Z coupé, these models are far from environmentally friendly. The former manages only 22.8mpg with emissions of 298g/km, while the latter is not a great deal better at 249g/km and 26.9mpg.

However, there is hope for the future. Nissan leads the way in electric vehicle technology, and we drive a prototype version of its five-door Leaf family hatch. It has a 100-mile range, can be charged to 80 per cent capacity in less than 30 minutes and should be on sale late in 2011.

BEST ECO BUY: Pixo