Despite the protests of those involved that all was above board, the news that Pirelli and Mercedes undertook three days of secret testing after the Spanish Grand Prix is very disturbing.
The laws of the sport do not allow in season testing by teams, however a loophole exists where Pirelli may request a team's assistance to develop tyres. The loophole is in itself senseless - Pirelli have historically maintained its own test car and driver for specifically this kind of thing.
Worse still, three days of testing for both Rosberg and Hamilton; in a car which has demonstrated phenomenal speed in qualifying and a total inability to keep tyres together during a race looks decidedly stupid at best, downright deceitful at worst.
I have no doubt that Pirelli's big concern here is keeping Mercedes happy -after all the company sells millions of cars, vans and trucks every year. Its also spending an indecent amount of money to win at F1 and at the moment is being held back by its problems with Pirellis tyres.
Understanding that, you can see how a veiled threat to keep Pirelli out of any future original equipment supplier agreements unless things improved would have them jumping around to keep the bosses in Stuttgart happy.
Machiavellian? Perhaps, but after nearly forty years of following F1 I'd say that its as good a theory as any. Unfortunately.
My question has to be: if it was all genuinely above board, why try to keep it a secret?