So Porsche is trying to get a judicial review called down on the proposed increase in London's congestion charge. First reaction: good on it - and it's a shame that other heavily affected companies (like Land Rover and Subaru) lack the guts to stick their heads above the parapet, too.

But if you're part of the 90 percent of the British population that lives outside greater London your reaction could quite possibly be one of shrugged shoulders and exhaled breath. Why, after all, does somebody need to drive their Porsche into central London between the hours of 7am and 6pm, Monday to Friday?

The thing is, this is an issue that's going to acquire a scary relevance for the rest of us - and sooner than most people realise. The technology and legislative framework for national road charging is being quietly assembled behind the scenes - and the view that vehicles with higher CO2 emissions are going to be hit disproportionately hard is in serious danger of becoming ingrained.

Put it this way - imagine that you live in Kensington and own a Porsche 911 that you keep on the road. Two years ago all you needed to do was to pay road tax and Kensington and Chelsea's resident parking fees. Then, against the wishes of the vast majority of local residents, the Congestion Charge was expanded westwards. As a bona fide resident you managed so secure the discounted rate - equivalent to 80p a day.