With the advent of the £1.30 litre of fuel and the 20 per cent tax rate, we think economical cars are going to be big news in 2010. Let us take you through the 10 most economical cars on sale in the UK, you'll not pay a penny for road tax on any of them.

As ever, let us know what you think and if there are other cars that should have been included.





1. Smart Fortwo cdi 86g/km Co2

The Smart fortwo cdi is the diesel version of the iconic two seater car range. The cdi has the lowest CO2 emissions of any other production car at only 86g/km; it also sips heavy fuel with a combined fuel figure of 85.6mpg. To sum up, the Smart Fortwo cdi is a Marmite car; you'll either love it or hate it. To achieve the amazing mpg figures that Smart claim, you need to buy into its unusual character which will not appeal to all.



2. Toyota Prius 89g/km Co2

This is the third-generation version of the petrol-electric car that brought green motoring to the masses, the Toyota Prius. The Prius looks good, is easy to drive, rides well, has a spacious interior and is well equipped. Sadly, all this cannot hide the lack of driver entertainment which is no better than any other hybrid.



3. Toyota Auris HSD 89g/km
Co2
Don't see yourself as a Prius driver? Don't worry Toyota may have come up with an answer – the Auris HSD. The HSD's 136bhp 1.8-litre petrol engine, combined with a hybrid battery pack could make it the most eco-friendly car on sale. It certainly has impressive figures to back this claim up, as CO2 emissions are just 89g/km and it's capable of 74.3mpg on the Combined cycle. Shame it's less practical than standard and isn't much fun to drive.



4. Skoda Fabia Greenline 89g/km Co2

Another member of the Volkswagen group's small green car arsenal is this – the Skoda Fabia Greenline. Powered by the same three-cylinder, 1.4-litre TDi diesel engine as the Ibiza and Polo which are also on this list. So why would you choose the Skoda over the SEAT and Volkswagen? Well, it looks attractive and has more passenger and luggage space.




5. Volkswagen Polo Bluemotion 90g/km
Co2
The first-generation Polo Bluemotion put Volkswagen firmly on the map as the producer of low emission cars. Even more fuel-saving green technology has been added for this second-generation model and the key figure is the 83.1mpg average fuel consumption. Alongside the amazing fuel consumption, the Polo emits just 90g/km of CO2 and could go 850 miles before need to be refueled. Downsides are that it's not the sportiest car to drive and the engine is noisy.




6. SEAT Ibiza Ecomotive 92g/km
Co2
The 76mpg Combined figure and 92g/km Co2 emissions are what makes this car so special. The Ibiza uses a 79bhp three-cylinder diesel engine, special front styling, lowered suspension and low rolling resistance tyres to cut through the air more cleanly. The Ecomotive looks good, is comfortable, fine to drive, free to tax and I regularly saw 60mpg when I drove it. Just don't mention the cheap feel to the cabin plastics, the noisy, peaky engine and the fact that you have to re-learn your driving style to get the best out of it.




7. Vauxhall Corsa 1.3 CDTi 95 Ecoflex 98g/km Co2
This Corsa might look like any other, but the green Ecoflex version was subtly tweaked for the 2010 model year. It's still powered by the same 1.3-litre CDTi, four-cylinder diesel engine; but it now produces 94bhp, mated with five-speed manual transmission. Previously voted as an engine of the year, it emits only 98g/km of Co2 and is now capable of 76.3mpg on the combined cycle. Downsides are that the engine is noticeably noisier and the hard ride won't suit all.




8. Ford Fiesta Econetic 98g/km
Co2
The Econetic is basically a green-tweaked version of the 89bhp 1.6 TDCi diesel Fiesta. The fashionable and stylish Ford scores well in the green buying stakes with its claimed 76.3mpg fuel economy that will rise to nearly 90mpg if you stick to motorways. CO2 emissions of only 98g/km are equally impressive, meaning road tax is free. The Fiesta is a great drive, but with the Econetic tweaks it's a green choice too. It's not a cheap option though, and key equipment such as air-conditioning is an extra.



9. Renault Clio eco2 98 g/km
Co2
Renault's electric range of cars are still a little way off, so if you want a green car from the popular French manufacturer, this Clio eco2 will have to do in the meantime. Powered by an 86bhp version of the 1.5-litre diesel engine, this Clio is capable of 76.3mpg combined consumption figure and emits just 98g/km of CO2. It looks the same as the standard car, but the eco2 version has taller gearing, revised engine electronics and uses low-viscosity oil.




10. Toyota iQ 1.0 99g/km
Co2
The iQ offers amazing packaging considering its size, the 68bhp 1.0-litre engine is a sweet performer, it's good fun to drive and it feels as well-made as you'd expect a Toyota to be. A miracle of interior packaging, in fact, the only disappointment is the price, which pits it squarely at bigger superminis such as the BMW MINI.