Sometimes you have to wonder how car-company PR mavens' minds work. Surely it would have been cheaper to give Italian-Iranian Pourmohseni Hadi a brand new M6 coupé, rather than push his buttons to the point where he parked the thing outside the main entrance to the 2013 Frankfurt motor show and beat hell out of it with a sledgehammer.

Hadi claimed that in 2010 his two-year-old E63 M6 developed a transmission fault, making rattling noises and jolting the whole car when changing gears.

WARNING LIGHT

What BMW didn't mention in their side of the ongoing debate was that the car agreed with him - the 'transmission fault' warning light on its dashboard had come on, and stayed on through several fruitless trips back to the dealer's workshop.

Even when the car came back with the light off, the problems persisted, according to Hadi, although BMW insisted that, according to the diagnostic computer, the car was now fault-free.

Unsurprisingly, Hadi then stopped paying for the car, and BMW Leasing Italia now has him and his company blacklisted as 'credit unworthy non-payers' - which has caused his business considerable financial embarrassment.

That's when he decided to go public - with a sledgehammer.

And even after that, BMW still refused to replace the M6, merely offering to buy the car back at a price that reflected five years' depreciation and the distance it had been driven in that time, without any public admission that it was inherently faulty.

"Not good enough," said Hadi and, having had the car restored at his own expense, drove it to Switzerland, where he parked it outside the main entrance to the Geneva motor show and - you guessed it - hauled out his favourite instrument of diplomacy again.

Ironically, when we checked the provenance of the video below in case of copyright issues, we discovered it was commissioned by Hadi himself, and has been viewed by more than 141 000 people in the week since it was posted.

It will take a lot more adspend than the €120 000 (R1.8 million) the M6 cost new to counter the effect of that much negative publicity.