• Drivers are paying over the odds thanks to unrealistic MPG claims
  • Lab-based data doesn’t reflect ‘real world’ driving conditions, research shows
  • Gap between the lab and on-the-road fuel economy is at its widest point, with an average car now using 24% more fuel than it should.
  • Audi A4, Hyundai Tucson, MINI Hatch and Ford Fiesta among the worst affected.
  • Findings based on 118,000 Real MPG fuel reports submitted by UK drivers.

The gap between advertised and on-the-road MPG is now at its widest ever point, with just 1 in 10 cars managing to hit their official fuel economy figures, according to new data from HonestJohn.co.uk.

The leading consumer-led motoring website analysed 118,000 Real MPG fuel reports, submitted by UK drivers, and found that an average car now uses 24% more fuel than it should.

The BMW X5 is the UK’s worst performing car for Real MPG, achieving 66.9 per cent of its advertised fuel economy, followed by the Land Rover Discovery Sport and Audi A4 with a respective 67.5 and 68.3 per cent. The Volvo XC90 (68.5 per cent) and Fiat 500X (69.6 per cent) complete the bottom five cars on sale right now for real world economy.

At the opposite end of the scale the latest Mazda MX-5 is the UK’s best Real MPG performer, with an average of 101.5 per cent. In second place is the Toyota Verso (99.5 per cent) followed closely by the GT86, with a real world fuel economy of 98.4 per cent. The final entries in the top five are the Subaru Forester (97.1 per cent) and Peugeot Partner Tepee (92.9 per cent).

Real MPG was launched in 2011 after HonestJohn.co.uk received thousands of complaints from readers that their cars could not match the ‘official’ EC fuel economy figures. Published at www.HonestJohn.co.uk/realmpg, Real MPG invites motorists to submit how many miles their cars actually do to the gallon, covering all major makes and models. Unlike official (laboratory tested) fuel consumption figures, Real MPG gives real life comparative data and allows car owners and buyers to see how much on-the-road fuel a vehicle really uses.

One of the reasons new cars have performed increasingly poorly is because, since 2015, car manufacturers have been fined if the corporate average CO2 emissions of their cars exceeds 130g/km according to MPG and CO2 laboratory tests. To avoid the fines, vehicles are increasingly optimised for the laboratory test at the expense of reality.

From September 2017, the current NEDC (New European Driving Cycle) test for new cars will be replaced with the Worldwide Harmonised Light Vehicles Test Procedure (WLTP). However, while the WLTP should be more reflective of real world driving conditions and involve longer distances and higher speeds, it will still be laboratory-based.

Honest John’s Managing Editor, Daniel Powell, said: “Real MPG has shown that, for the majority of drivers, advertised fuel economy figures are quite simply too good to be true. As a result, many are finding it increasingly difficult to understand how much fuel a car will use or how polluting it will be.

“We welcome the introduction of the new Worldwide Harmonised Light Vehicles Test Procedure (WLTP), but it remains to be seen if this new laboratory-based test will provide the realistic figures that the public have been crying out for – there’s clearly a need for change in the way that MPG is measured, as the real world figures don’t reflect those of laboratories.”

The worst cars on sale in terms of disparity between claimed and Real MPG fuel economy are:

 1) BMW X5  66.9%
 2) Land Rover Discovery Sport  67.5%
 3) Audi A4  68.3%
 4) Volvo XC90  68.5%
 5) Fiat 500X  69.6%
 6) MINI Hatch  70.0%
 7) Peugeot 308SW  70.2%
 8) Range Rover Evoque  70.4%
 9) Ford Fiesta  71.0%
 10) Hyundai Tucson  71.3%

The best cars on sale in terms of disparity between claimed and Real MPG fuel economy are:

 1) Mazda MX-5 101.5%
 2) Toyota Verso  99.5%
 3) Toyota GT86  98.4%
 4) Subaru Forester  97.1%
 5) Peugeot Partner Tepee  92.9%
 6) Suzuki SX4 S-Cross  92.0%
 7) SEAT Mii  90.6%
 8) Volkswagen Jetta  90.4%
 9) Suzuki Swift  90.1%
 10) Volkswagen Scirocco  88.6%


HonestJohn.co.uk is the website that champions for fairness to car owners by publishing expert, unbiased information to help consumers make informed choices about their cars. The site has more than 2.0m unique visitors each month.

The website was established in 2000 in response to reader questions to the Honest John column in Telegraph Motoring. It gives free advice and information and aims to help raise standards for the consumer. It provides honest answers to direct questions about the best cars and the best deals for consumers, written clearly and displayed in a user friendly way.

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