Even with petrol and diesel prices dropping, fuel economy is still a high priority for most motorists. A car that's cheap to run will save money, save the planet, and even keep its value better than a gas-guzzler when it comes to resale time.
Thats why we've listed the top petrol and diesel models for fuel efficiency here. Do be aware, however, that the greenest versions are not always the best cars in the range to go for - it can often be better to save money on the list price and go for a less economical model, or switch to a petrol car to avoid more expensive repairs. Economy is just one factor to consider but it can be a big one.
Although official fuel economy and CO2 emissions figures are often quite different to the real-world figures, we still see them as useful. The official economy tests are standardised, so they don't include variations in driving style, traffic or weather - that means they are comparable, and a higher figure on the tests will likely mean a higher real-world figure, too.
We've decided to focus on non-hybrid and non-electric cars in our list here, as we've already put together round-ups for those models (see links, below). Instead, we’ve concentrated on conventionally-engined cars - especially as they are often much more affordable than their electrically-powered equivalents.
Electric cars do work for some people, though, so if you're looking for ultra-low emission vehicles, we've also got articles on the best hybrid cars, the best electric cars and even the best green cars on sale now.
Do remember that small diesel cars often boast excellent economy but this may not suit your lifestyle. Small city cars are great for commuting into town, but the tiny dimensions and cramped interior mean family trips can be very uncomfortable indeed - and there won't be much space for the shopping.
Diesel engines are not suitable for short trips, but work best for motorway travel - and small petrol engines are the opposite, working well in the city and getting noisy on faster roads. Also, diesel cars are usually more expensive than their petrol equivalents and are more costly to fill up. So if you don't cover long distances, a petrol car could make more financial sense.
You need to think carefully about which car will suit your needs best before you make a decision, rather than thinking purely about the fuel economy.
The cut-off point for our most economical cars list is an astonishing combined cycle return of 85.6mpg. Below that sit a cluster of fantastic cars that average over 80mpg but didn't quite make it into the fuel efficiency hall of fame. Any one of them should still be seriously cheap to run. Here's the best of the rest...
Citroen C3 1.4 e-HDi Airdream - 83.1mpg
Citroen C4 Cactus 1.6 BlueHDi - 83.1mpg
Ford Focus ECOnetic - 83.1mpg
Peugeot 208 1.4 e-HDi - 83.1mpg
Volvo V40 D2 - 83.1mpg
Skoda Fabia Greenline Estate 1.2 TDI - 83.1mpg