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10/06/2025

The UK's most efficient cars revealed

Written By Phill Tromans

Suzuki Celerio

If you're looking to spend less at the pumps, it might be time to turn to Japan.

New Real MPG data from HonestJohn.co.uk has revealed the most fuel-efficient cars on Britain's road, using real-world data rather than lab test or marketing claims. The research draws on the experiences of more than 250,000 motorists, and it paints a clear picture – when it comes to real-world fuel economy, the charts are topped by Toyota, Suzuki and Nissan. Whether you're after a petrol, diesel, hybrid or plug-in hybrid, the Japanese trio deliver the best miles per gallon.

Petrol power: Suzuki leads the pack

Petrol cars are still the most common choice for British drivers, and Suzuki has taken a clean sweep of the podium sports for real-world efficiency. The 2015-2019 Suzuki Celerio 1.0 DualJet tops the list, with drivers achieving an impressing 70.1mpg. Close behind is the 2016-2019 Suzuki Baleno DualJet with 63.5mpg, and the 2017-2024 Suzuki Swift 1.0 BoosterJet Hybrid is third.

Nissan Micra frontleft exterior
The Nissan Micra diesel nudges 70mpg on long distances.

Diesel power: Nissan leads the way

While diesel might have fallen out of a fashion, it's still smart choice for long-distance drivers, and Honest John readers say the 2017-2022 Nissan Micra dCi 90 is the best option, with a Real MPG figure of 69.6mpg. That's some way ahead of the SEAT Ibiza 1.4 TDI Ecomotive (66.5mpg) and the Fiat Panda 1.3 MultiJet (66.4mpg).

Hybrids: Toyota takes the crown

When it comes to hybrid cars, Toyota remains the undisputed champion. The 2021 Yaris Cross Hybrid recorded a Real MPG of 70.5mpg, with the standard Yaris Hybrid hot on its heels at 69.6mpg. Suzuki appears again with the (Toyota-based) Swace, delivering 65.5mpg.

Toyota Prius (2016-2022) Review: rear static
The Toyota Prius's plug-in capability is second to none.

Plug-in hybrids: Toyota again

Plug-in hybrid MPG figures can vary wildly depending on how and when they're charged. But even so, some models clearly stand out. The Toyota Prius Plug-In Hybrid (2017-2022) gets a remarkable 133.5mpg based on everyday driving data. The Hyundai Ioniq Plug-in (129.5mpg) and the Audi A3 E-tron (107.3mpg) also perform strongly.

Why is Real MPG different?

Unlike the WLTP (Worldwide Harmonised Light Vehicle Testing Procedure) figured provided by manufacturers, Real MPG is based on everyday use, such as school runs, motorway commutes, or weekend getaways. This means it offers a more realistic view of how for fuel will actually get you.

David Ross, the senior editor at HonestJohn.co.uk, said: "While [WLTP] is said to closely replicate real-world usage, it’s only in daily use when you can truly assess how economical a car really is, and the Real MPG data has shown us some clear differences between WLTP figures and those achieved by HonestJohn.co.uk readers. One thing is certain, though, and it’s that Japanese brands came out on top for Real MPG performance."

What about electric cars?

While the rise of electric vehicles (EVs) continues, HonestJohn.co.uk notes that it's still too early to offer meaningful comparisons. However, that's set to change with the upcoming launch of Real Range, a similar project focused on electric vehicle performance.

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