We test new cars’ fuel economy every week at What Car?, but unlike the laboratory-derived Government data, our True MPG technicians gain the numbers from driving in real-world conditions, to bring you realistic MPG figures.
Here are the 11 most economical small petrol cars on sale in the UK today.
1. Mitsubishi Mirage 1.2 – official 65.7mpg True MPG 53.4mpg
Every version of the Mitsubishi Mirage emits less than 100g/km of CO2, and the little car performs admirably in our real-world economy tests. That's about the only good thing we can say about it, though, because it falls short of the competition in almost every other area.
2. Suzuki Swift 1.2 – official 50.0mpg True MPG 51.7mpg
The Swift offers great value for money, and our MPG tests show it should be reasonably cheap to fuel. In 1.2 guise it managed 51.7mpg in the hands of our technicians, which is 1.7mpg better than its official figure.
3. Mazda 2 1.5 89 Skyactiv-G – official 62.8mpg True MPG 50.8mpg
The Mazda 2 falls a fair way short of its official fuel economy, but a True MPG result of 50.8mpg is still a commendable result in the real world. The engine tested here is the middle of the three power outputs, with 89bhp from the 1.5-litre petrol.
4. Volkswagen Polo 1.2 TSI 90 5dr – official 60.1mpg True MPG 47.4mpg
Buyers after a premium small car need look no further than the Polo. It's refined, well priced and comes with a classy interior. In our real world tests, it didn't match the claimed 60.1mpg, but 47.4mpg is respectable.
5. Ford Fiesta 1.0 Ecoboost 125 3dr – official 65.7mpg True MPG 46.2mpg
The Fiesta is the UK’s best-selling car, and this is the most efficient petrol version you can buy. The Government test result is a lofty 65.7mpg, but in our real-world driving it managed 46.2mpg.
6. Renault Clio 0.9 TCe 90 – official 62.7mpg True MPG 45.8mpg
The Renault Clio is a stylish, refined small car that isn't far behind the class leaders. The 0.9-litre three-cylinder petrol engine isn't the fastest but it makes up for that by returning 45.8mpg in real-world conditions.
7. Skoda Fabia 1.2 TSI – official 60.1mpg True MPG 44.9mpg
Our Car of the Year 2015 is a great small car - it's well equipped, good to drive and undercuts its main rivals on price. It can't quite match the 60.1mpg official figure, but returned a respectable 44.9mpg in our True MPG tests.
8. Peugeot 208 1.0 VTi – official 65.6mpg True MPG 44.7mpg
The Peugeot 208 looks good inside and out, even if some of that style does compromise function when it comes to the dashboard. The 1.0-litre petrol is reputed to return 65.6mpg, but we achieved 20mpg less than that in our tests.
9. Vauxhall Corsa 1.0i 90 – official 64.2mpg True MPG 43.6mpg
The new Vauxhall Corsa is a decent small car but it can't quite compete with the Ford Fiesta when it comes to driving enjoyment or the VW Polo in terms of interior quality. The 1.0-litre petrol engine managed 43.6mpg in our True MPG tests.
10. Toyota Yaris 1.3 VVT-i – official 52.3mpg True MPG 43.4mpg
Yaris buyers get a spacious, well equipped small car at a decent price, although they have to put up with a plasticky interior. We achieved 43.4mpg in our real-world tests.
11. Smart Forfour 0.9 90 – official 65.7mpg True MPG 43.3mpg
This version of the Smart Forfour is definitely the one to choose if you take to the motorway on a regular basis. It's also capable of 43.3mpg in real-world conditions. The Forfour is deceptively spacious inside, but not as much fun to drive as some of its rivals
Visit whatcar.com/truempg to see the full range of cars we’ve tested to find out what you really can expect to achieve on UK roads.