Vauxhall facelifted the Insignia last year, tweaking the engine in the process to put the car clear to the
top of the class for CO2.

Our 140hp 2.0 CDTi emits 98gkm, and the only other rival to get below 100g/km is the diesel-hybrid Peugeot 508, but it’s expensive to buy, and its straight-diesel variants come in at 104g/km for the 115hp version and 119g/km for the 140hp. Ford’s Mondeo manages a low of 109g/km for its 115hp engine, but, by comparison, a whopping 130g/km for the 140hp.

The story’s the same for the Mazda 6, VW Passat and Skoda Superb – all have emissions at least 6g/km higher than the Insignia