This time last year I wrote about diesel still being the right choice of fuel for some drivers. A reader got hold of my phone number and, after a heated debate, accused me of playing an active role in the deaths of my children (who had been pictured in a report about a long-term test car, a diesel-powered Skoda Kodiaq).

It was, I must admit, quite an emotive finale (yes, I bade him farewell pretty soon afterwards) to a conversation that had, up to that point, been notable for both of us quoting ‘facts’ at one another that we each passionately believed in.

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My view boiled back to the fact that the very latest diesels - independently tested by What Car? as part of its True MPG real-world efficiency analysis - were producing NOx and particulate figures in line, and sometimes better, than petrol engines that had been put on sale just 18 months earlier. 

I was aware that my point of view mirrored that of the car industry, something that always worries me, as I don’t want to be a stooge who just parrots one side of an argument, but - to stress again - it was backed by the results of our own testing. 

His argument, however, was based on the pronouncements on a multitude of academics and doctors, all damning diesel. It takes a pretty special kind of arrogance for a journalist to deny experts in their field, but I still believed that none of the evidence being presented was applicable to the latest diesels that were only just coming to the market. 

But what did I know, especially when this time last year there was a mountain of rhetoric to support his stance, much of it pushed out by various government departments (but principally Michael Gove as Environment Secretary) and all of which had built up to a point that ‘dirty diesels’ (regardless of age and emissions-reducing capabilities) had become a staple of the front pages for a period?

Now, 12 months on, is it time to reassess the so-called facts? I think so, chiefly because the idea that modern diesels are part of the solution rather than problem is gathering pace, the arguments now backed by the results of the new, tougher-than-ever WLTP test regime that has been rolled out across Europe and which - even attackers of ‘old’ diesels are starting to admit - are proving the significant gains that have been made.