Eco-friendly cars-Blue is the future.

1: Seat Ibiza, 1.4 TDI 80PS Ecomotive, diesel

CO2 (g/km): 99

Price: £11,000

Seat's probably not the first name you think of when it comes to green cars, but this three-door supermini's both cheap to buy and cheap to run.




2: Volkswagen Polo Bluemotion, 1.4 TDI 80PS

CO2: 99

Price: £11,995

This little diesel has all the solid German build quality you'd expect, plus an incredibly economic engine that'll make the man at the garage a distant stranger.



3: Honda Civic Hybrid 1.4 IMA ES

CO2: 109

Price: £16,300

As the cheapest hybrid in the UK, the Honda Civic Hybrid is a good, small family alternative to the Prius -- so long as you can stomach automatic transmission.



4: Renault Megane Sport Hatch 1.5 dCi 86 Expression 3 door

CO2: 117

Price: £13,000

Like Citroen, Renault's one of the unsung French brands which has been doing a huge amount to cut emissions across its range. This small family car is a particularly economic example.



5: Citroen C3 1.6HDi

CO2: 118

Price: £13,000

The Citroen C3 is an efficient, straightforward car with a big boot and not quite enough legroom at the back.




6: Ford Focus ECOnetic 1.6 TDCi

CO2: 115

Price: £15,800

This is a brand new version of Britain's most popular car. It's incredibly fuel-efficient and, if it's similar to the Ford bioethanol Focus we reviewed, will make for a good reliable drive.



7: Renault New Laguna Hatch dCi 110

CO2: 130

Price: £17,100

As it emits 130g of CO2 per kilometre the Laguna is just on the borderline of being a greener option, and it's also on the pricey side. But it has some of the best green creds you'll get for a car of this size.



8: Skoda Fabia Estate1.4 TDI PD 80PS

CO2: 109

Price: £13,100

No more funny jokes about Skodas. This one is big and clever -- not to mention as cheap and green as estate cars come.



9: Peugot 207 SW, 1.6 HDi

CO2: 119-123

Price: £13,900

Another big but green option. According to Autoexpress it's a little dear, but it has everything you could want in an estate.



10: SMART Fortwo Cabrio

CO2: 113

Price: £10,500

With their heavier frames for safety and structure, it's surprising any open-top cars made this list. But we can fully recommend this Smart, since it emits so little CO2 and only costs mite over £10K.

You can see more low CO2 cars by class on the Government's Best on CO2 site .