It now looks like Porsche will be seeking a judicial review of the Mayor of London’s decision to bring in a £25 per day charge for vehicles in Band G. Porsche have written a letter to the Mayor and, if he doesn’t reply in 14 days, they will head – expensively – for the courts.

Andy Goss, MD of Porsche UK, says the "massive congestion charge increase is quite simply unjust." A spokesman for Mayor replied that "No-one is allowed to throw their rubbish in the street and Porsche should not be allowed to impose gas-guzzling, polluting cars on Londoners who do not want them.”

There’s a very serious point to be pursued here. Porsche, and the rest of the car industry, must wrest back the meaning of the word pollution from the grip of the Green spin machine. Gas-guzzlers they maybe (though I’d bet the average Porsche does far fewer miles in a year than the average Mondeo), but they certainly aren’t polluters.

Like all modern petrol-fired units, Porsche engines are as clean a whistle. Indeed, if you replaced all 21,000 black cabs with 21,000 Cayennes, inner London’s air quality would improve massively overnight. Recently, a blogger pointed out that when his imported Dodge Durango 5.7-litre V8 was tested by VOSA, the equipment could barely register pollutants from the engine.

What matters in the city centre is air quality and London’s is probably the worst in Europe. Worst because of the use of big diesel engines, in big heavy vehicles, trapped in stop-start traffic. And that’s nothing to do with Porsche, or any other car maker.