Real-world MPG: last 12 months' most efficient cars

What Car? has tested over 200 cars in the last year. Find out which models are the winners and losers...

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Matthew Burrow
25 Mar 2015 14:34 | Last updated: 14 Jun 2018 0:3

The most fuel-efficient car tested by the What Car? True MPG team over the last 12 months – topping more than 200 other models – was the Seat Leon 1.6 TDI 110 SE Ecomotive 5dr, managing a real-world average fuel economy figure of 63.2mpg.

Since launching True MPG in 2012, more than 600 cars have been assessed in real-world conditions achieving economy figures that are an average of 20% lower than the official figures.

Even the Seat’s table-topping figure was below its claimed figure of 85.6mpg – a result of manufacturers being forced by legislation to test their cars in laboratory conditions.

The Citroën C3 VTR+ e-HDi Airdream remains the most efficient car, on the road according to True MPG analysis, achieving 70.3mpg.

The testing has also highlighted an unexpected trend among high-performance cars for getting closest to their official claimed fuel economy figures.

While far from the most economical overall, the Aston Martin V8 S, which packs 430bhp, beat its official fuel economy figure by 6% – achieving 23.2mpg instead of 21.9mpg.

Another powerful V8-powered sports car, the new Jaguar F-Type R, was the only other vehicle to achieve the same feat during the past 12 months, with a True MPG figure of 25.7 compared with its official 25.5mpg.

Alternatively, the Ford Fiesta Zetec S was furthest away from its official fuel economy figure, coming in 37% below claimed consumption figures.

We add new models to our True MPG database every week. Visit to see the full range of cars we’ve tested, and find out what you really can expect to achieve on UK roads.