In the course of just a few days, the Volkswagen (VW) test-cheating scandal has provoked a series of responses.
In turn, we have seen dismay and anger from environmental campaigners and consumers alike, a collapse in the company's share price, then a political backlash that could yet transform our approach to air quality and vehicle emissions-testing. Now there is talk of criminal investigations.
One of the biggest names in motor manufacturing, if not down and not out, is on the ropes and reeling.
A household name has become a dirty word overnight.
So just what effect will the VW emissions revelations have as the European Parliament moves towards a plenary vote on air quality in October?
As the Parliament's rapporteur on this legislation, I believe the scandal will focus our attention still further on what can be learnt from the US, the place where this cheating was detected and where the story broke. If what has emerged from America is not a complete game-changer for this field, I believe it has utterly changed the mood.
The US runs a very different system of regulation from Europe. There they set standards and then do random tests (known as surveillance testing) on vehicles. Put simply, they take cars off the road and test them for emissions performance throughout their on-road life.
In the EU, by contrast, we set so-called type approvals. That means we lay out the performance standards on new vehicles, test them and then put them on the road without any further testing. We assume that what happens on the road for the car's life is the same as at the pre-launch test station.
For a while there have been questions about the efficacy of the tests in Europe and we are working hard to improve the real-world driving conditions employed in the tests.
However, even before that is considered, the big question is this: in the EU, could it be that the same software which VW installed in vehicles in the US to produce false test results was also used on these type approvals in Europe?
Over the last decade, the EU Commission and the industry have known that on the road, in real driving conditions, vehicles do not perform as the tests suggest they would. Can that really remain the status quo?
Or do we now need to move, as I suggested in my report may be a possibility, to a US surveillance style regularity system in Europe?
Let us be clear - that would be expensive and bureaucratic. Therefore, we need an urgent answer to the question of whether, as some environmental pressure groups have suggested, this fraud has been used in Europe, be it by VW or by anyone else.
Until that is addressed, the questions for policymakers and motorists alike will be: if a company as big and reputable as Volkswagen could buck the system - how can we trust the system at all?