Of all the cars we tested in 2012, the ultra-efficient small cars showed the greatest difference between our own mpg tests and the EU tests used by manufacturers.
Fuel efficiency tests
In fact, all 10 of the cars with the largest disparity between claimed mpg and our test results are ‘eco’ models that claim to beat the 100g/km CO2 emissions mark.
The worst offender is the Peugeot 208 1.4 e-HDi EGC automatic, which our test found to be an astonishing 21.7mpg short of Peugeot’s claim. That could cost drivers an extra £327 a year. The biggest cost difference revealed by our tests was the Fiat Punto TwinAir, at £366 a year.
Read how our mpg tests differ from the European test cycle used by car manufacters. And if you want fuel tests you can trust, sign our petition.