True MPG: most and least efficient cars revealed

We take a look at all the most efficient cars in the real world - and the least...

What Car?’s True MPG real-world fuel economy figures show what sort of efficiency you can really expect from a carImage 1 of 21

Tests are conducted in a laboratory under tightly controlled conditions to ensure repeatability within 1%, but they're based on a real-world route that takes in town, rural and motorway driving.

The results reflect what's achievable if you’re driving gently and sticking to speed limits, but aren’t resorting to any unrealistically slow acceleration or special 'hypermiling' techniques.

As a result, True MPG is not only fully reflective of real-world performance, but much more realistic than the official government fuel economy figures that car manufacturers have to quote.

The latest models to be tested are the Hyundai i10 1.0 MPi city car, which returned a highly creditable 49.9mpg; the Ford Fiesta 1.0 Ecoboost, which wasn't far behind on 45.5mpg; and the racy Ford Focus ST hot hatch, which could manage only 29.6mpg. But how do these figures compare with those of the best and worst cars we've ever tested? Let’s start off with the most fuel-efficient: