The car was chosen from a final shortlist of ten “green” cars which were all put through their paces by six of the United Kingdom’s leading environmental and transport experts. The other nine cars in contention for the prize were the Mitsubishi i-MiEV electric, Citroen C1 ev’ie electric, Ford Fiesta ECOnetic, Toyota iQ, Volvo S40/V50 DRIVe start-stop, Volkswagen Passat BlueMotion 2, third-generation Toyota Prius hybrid, new Honda Insight hybrid, Citroen C3 Picasso compact-MPV and the BMW 318d saloon.

Having a more compact, and therefore more lighter, power-train, the Prius is greener than ever before. It has an official combined fuel economy touching 72.4 mpg and its CO2 emissions are only 89g/km, which is an impressive 14% improvement over the current model. The new Prius utilises a new 1.8 litre petrol engine (four cylinders), as opposed to the 1.5 litre engine in the current model. This improves overall fuel economy as well as giving additional driver control.

However, the Insight is only estimated at getting 40 mpg city / 43 mpg open road, lower than the Prius.  It does, though, have several new bells and whistles that Honda hopes will appeal to the younger crowd, including a dashboard that resembles a video game display.

According to Toyota, the new Prius will get about 50 mpg in town and about 49 on the open road, up a few mpgs from the current version.  This is better mileage than the Prius’s main competitor, the Honda Insight.  The 2010 Prius also includes a 1.8 litre engine and an all-electric water pump, air conditioner, and power steering—there are no belts anywhere.

As far as looks go, the 2010 Prius is a bit shapelier and more aerodynamic, saving yet a bit more petrol.  It also includes a solar panel on the roof that keeps the car’s internal fan running while you’re out of the car running errands.  This reduces the drain on the air conditioning.  The new Prius will be available at the end of May.