Modern cars have never been more economical to run. The best new green cars continue to set mpg records, with the most fuel efficient returning more than 80 miles per gallon.
And with fuel prices in 2011 continuing to rise fast, it is now more important than ever before to own a fuel-efficient car.
The most economical cars also put out the lowest levels of CO2 emissions - meaning they are green cars in every sense of the word.
As an added bonus, all these cars get free road tax - and they can even now travel into the London Congestion Charge zone for free, too!
So which ARE the most economical cars in Britain? MSN Cars is committed to bringing you details of the cars with the best fuel economy on sale in the UK.
1. Smart Fortwo cdi - 86g/km
The most economical new car on sale in Britain is the Smart ForTwo cdi diesel. It returns an incredible 85.6mpg!
It is not the fastest or most refined car on sale, but there is no questioning its fuel efficiency. Pity it seats only two.
New Fortwo cdis cost from £9,825.
2= Toyota Auris Hybrid T4 - 89g/km
The newest Toyota Hybrid is the British-built Auris HSD. This uses the same petrol-electric running gear as the Prius, and returns an amazing 74.3mpg average fuel economy.
This is better than the Toyota Prius, despite the same CO2 figure. Auris fuel economy is better in town, whereas the more aerodynamic Prius wins on a long run: the weighting of economy stats mean the Auris gets the 'official' nod. Which would be best for you?
New Auris Hybrids cost from £19,545.
2= Toyota Prius T3 - 89g/km
Toyota sells another hybrid family car alongside the Auris HSD - the world famous Toyota Prius.
The T3 is the base variant, whose smaller (and lower-drag) 15-inch alloy wheels help the petrol-electric hybrid to 72.4mpg, and CO2 emissions of just 89g/km. It also does 76mpg on a run, beating its Auris Hybrid sibling.
New Priuses cost from £20,695.
2= Skoda Fabia Greenline II - 89g/km
VW Group sells three cars with the efficient 1.2-litre TDI diesel engine - and it is the super-practical Skoda Fabia Greenline II that is the most fuel efficient.
It emits just 89g/km CO2 and returns a heady 83.1mpg. Here at MSN Cars, we would trade the 2.5mpg it gives to the Smart in return for its five-seat practicality.
New Fabia Greenlines cost from £13,685.
3. Volkswagen Polo Bluemotion - 91g/km
The Volkswagen Bluemotion range is one of the most well-known fuel saving new car line-ups on sale in the UK.
The latest Polo Bluemotion is the most economical of the lot. It averages 80.7mpg and emits just 91g/km CO2.
New Polo Bluemotions cost from £14,860.
4. SEAT Ibiza E Ecomotive - 92g/km
The sporting Spanish VW Group brand, SEAT, matches the Polo Bluemotion for fuel economy with the SEAT Ibiza E Ecomotive.
It is the smallest of differences that leads to an extra 1g/km CO2, but to all intents, the two are just as economical - making the cheaper-to-buy SEAT the preferred choice?
New Ibiza Ecomotives cost from £13,900.
5. Lexus CT 200h SE-I - 94g/km
The latest hybrid car to go on sale in the UK, the Lexus CT 200h uses technology derived from the world-famous Toyota Prius.
It is very economical, averaging 69mpg, and blends this with low CO2 emissions and a premium image. But is the fuel-efficient new Lexus a genuine Audi A3 alternative?
New Lexus CT 200h SE-Is cost from £23,485.
6= Fiat 500 TwinAir 85 - 95g/km
Fiat has fitted a revolutionary two-cylinder petrol engine to the funky 500, which boasts great fuel economy - it can average nearly 69mpg.
The powerful motor still produces 85hp though, thanks to the addition of a turbocharger. This doesn't impact on CO2 emissions: they are super-low at just 95g/km.
New Fiat 500 TwinAirs cost from £10,865.
6= Fiat Punto Evo 1.3 MultiJet 85 Eco - 95g/km
Fiat has revised the Punto Evo again, to make it even more fuel efficient. The latest version can average over 78mpg.
Ongoing tweaks to the 1.3-litre MultiJet diesel engine have also cut CO2 emissions to just 95g/km. A bargain-priced, practical fuel-saver.
New Punto Evo Multijets cost from £12,195.
7= Ford Fiesta Econetic - 98g/km
The Ford Fiesta Econetic gives you exceptional 76.3mpg diesel fuel economy AND exceptional driving entertainment behind the wheel.
It is a superb all-rounder with the added benefit of free road tax, thanks to CO2 emissions of just 98g/km.
New Fiesta Econetics cost from £13,895.
7= Vauxhall Corsa 1.3 CDTi 95 - 98g/km
Vauxhall is never one to be outdone by arch-rival Ford. The facelifted Corsa is now available in 1.3 CDTi 95 ecoflex guise, which emits just 98g/km CO2.
It also matches the Ford Fiesta Econetic's fuel economy, with a great average of 76.3mpg. Stop-start also helps fuel economy in town, too.
New Vauxhall Corsa CDTis cost from £13,310.
8= Toyota IQ 1.0 - 99g/km
The fuel-efficient micro car alternative to a Smart that CAN seat more than two people is the Toyota IQ. With sub-100g/km CO2 emissions, it really does justify its name.
The Toyota is going to get even more attention soon, as Aston launches its IQ-derived Cygnet. Will Aston, in time, launch a similarly green version using the same 1.0-litre petrol engine as this?
New Toyota iQs cost from £10,445.
8= Peugeot 207 Economique - 99g/km
Peugeot's 207 range is getting on a bit now, but it is still able to challenge its rivals in terms of fuel efficiency.
In 1.6 HDi Economique guise, it is another car to crack the magic 74mpg benchmark, and again emits just 99g/km CO2.
New Peugeot 207 Economiques cost from £13,045.
8= Audi A3 1.6 TDI 105 - 99g/km
The Audi A3 is an established premium hatchback - but this does not mean it's a gas-guzzler. In 1.6-litre TDI guise, it is capable of 74.3mpg.
CO2 emissions of under 100g/km also prove that you can go upmarket without affecting your green credentials.
New Audi A3 TDIs cost from £18,700.
8= Citroën DS3 Dstyle - 99g/km
The radical Citroën DS3 is the French brand's answer to the MINI. It is similarly green though, with average economy of 74.3mpg.
CO2 emissions are low and they're cleaned up further by a standard particulate filter.
New DS3 Dstyles cost from £14,100.
8= Citroën C3 Airdream+ - 99g/km
If the Citroën DS3 is not practical enough for you, Citroën also offers the C3 supermini in similarly economical Airdream+ guise.
This has the same super-efficient 1.6-litre HDi engine, meaning it also has CO2 emissions that dip below the 100g/km barrier.
New C3 Airdreams cost from £15,090.
8= Ford Focus Econetic - 99g/km
The outgoing Ford Focus is still available at dealers if you search hard enough - and it's worth hunting for a great deal on the Econetic version.
The great-handling Ford emits 99g/km and matches the VW Golf Bluemotion for fuel economy, averaging 74.3mpg.
The current Focus range starts from £15,871.
8= Volkswagen Golf Bluemotion - 99g/km
The Volkswagen Golf Bluemotion is a premium-finish family hatchback with supermini-like fuel economy. 74.3mpg from such a refined car is staggering.
MSN Cars is running a VW Golf Bluemotion as a long-term test car - and we are finding the economy lives up to the great official claims in practice, too. Even more impressive!
New Golf Bluemotions cost from £18,665.
8= Volvo C30 DRIVe - 99g/km
The stylish Volvo C30 DRIVe was one of the first 'super-eco' cars on sale. Volvo has just refreshed the diesel engine for 2011 - it now produces 115hp.
It's still very economical, though. 74.3mpg is great and stop-start cuts CO2 emissions to 99g/km. Not big enough for you, though? Read on...
New C30 DRIVes cost from £18,905.
8= Volvo S40 DRIVe - 99g/km
Yes, the Volvo C30's 4-door sibling, the Volvo S40, is also available in DRIVe guise.
Despite its extra space and five-seat capacity, it retains the same amazing 74.3mpg economy figure...
New S40 DRIVes cost from £21,045.
8= Volvo V50 DRIVe - 99g/km
Or maybe you need the extra boot space of an estate? Even here, Volvo has a 74mpg answer, with the Volvo V50 estate.
Even with its 99g/km CO2 figure, it still manages to boast an ample 1,307-litre boot with the seats folded.
New V50 DRIVes cost from £22,425.
8= SEAT Leon E Ecomotive - 99g/km
The SEAT Leon E Ecomotive is a cheaper alternative to the Volkswagen Golf Bluemotion. It isn't as luxuriously finished but it looks sportier and has sharper handling.
It still has the same 74.3mpg economy figure though - and the 1.6-litre TDI engine still produces 99g/km CO2.
New Leon Ecomotives cost from £17,355.
8= MINI Hatch One D - 99g/km
The original UK economy car has kept pace with the times. The latest One D variant uses all the latest BMW engine technology to emit less than 100g/km CO2.
Standard stop-start also means the 74.3mpg average economy won't be affected too much by the city centre traffic it thrives in, either.
New MINI One Ds cost from £14,175.
