Wandering around the Autosport Show last week, I had a strange bottle of fluid thrust into my hands. "Put this in your engine," advised its bearer, "and not only will its performance be improved, but its fuel consumption and emissions will be cut too."

We have, of course, all been here before and for the avoidance of all doubt I should say now that this stuff, which rejoices in the name Bor Power, has yet to visit the inside of any engine of mine, so I am in no position to say whether the outrageous claims for it – a nine per cent increase in engine performance, a 15 per cent reduction in emissions and fuel consumption – will withstand the slightest scrutiny.

Besides, I am cynical in general about all quick-fix solutions and suspicious in particular of engine additives such as this. As you might imagine, quite a few of these alleged miracle cures have floated before my eyes in the last couple of decades working for Autocar and, while in fairness I can’t remember any reducing an engine to shrapnel, none stand out as having made a blind bit of difference.

In fact the only reason I mention this product now – which comes from the world of nanotechnology and claims to line your engine with boron diamond powder crystals 100,000 times narrower than the width of a human hair – is that it’s been tested and certified by one of the four German ‘TUV’ independent validation organisations. Their tests did not extend to measuring performance gain, but they did show that Bor Power reduced the fuel consumption of a Merc S320CDi from 24.8mpg to 27.0mpg, while reducing CO2 emissions from 300g/km to 276g/km.