Another new day, another opportunity for the ramifications of VW’s efficiency cheating scandal to bounce around the world on social media and, increasingly, in the pages of the tabloids.

A crafty way to get around the emissions tests on half a million US-market diesel cars is worthy of a mention, it seems; the confession that the crisis could in fact affect 11 million vehicles worldwide has made the people’s car the people’s news.

In so doing, it has muddied the waters - to the point where it’s worth clarifying exactly which test VW has admitted to twisting. For this not a question of fuel economy or CO2 figures; it is about the potentially more harmful NOx particulates that are causing so many issues in traffic-heavy cities worldwide. The mainstream media - keen to tap into the pent-up frustration about the official fuel economy figures - has been quick to ask questions on the shortfall between those numbers and what we can all achieve in the real world. It’s an issue, no doubt - and one that our sister title What Car? has tried to address with its True MPG on-the-road tests. But it’s not what’s at stake here.

If anything, NOx has the potential to become a bigger issue than CO2 has ever managed to be. Sure, the big manufacturers bleated when they were set aggressive fleet average targets - and Winterkorn himself spoke out on the matter at last autumn’s Paris motor show, revealing that every 1g/km of CO2 emissions reduction costs VW 100 million euros. But the industry continues to hit and surpass those CO2 goals - allowing millions of motorists to save on taxes and claim the environmental high ground, often by choosing diesels.