The Suzuki Ignis is the most fuel efficient car we've ever tested, averaging an impressive 59.6mpg on our True MPG tests, while at the other end of the scale we also have a new worst-performing car in the Audi SQ5, which managed just 24.6mpg.
What Car?'s True MPG tests are conducted in a laboratory under strictly controlled conditions, but based on a real route that takes in town, rural and motorway driving.
Below we take a look at all of the cars we've tested in June and July, revealing the fuel economy you can really expect them to deliver on UK roads.
Audi Q5 2.0 quattro S line S tronic
Official fuel economy: 55.4mpg; True MPG: 41.0mpg; Shortfall: 26.1%
Official fuel economy: 33.2mpg; True MPG: 24.6mpg; Shortfall: 25.8%
BMW 5 Series Touring 520d M Sport
Official fuel economy: 62.8mpg; True MPG: 44.9mpg; Shortfall: 28.5%
Mazda 6 2.2d SE-L Nav
Official fuel economy: 68.9mpg; True MPG: 47.3mpg; Shortfall: 31.3%
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