I must admit that I already have trouble thinking about Norwich without mental reference to that city's most famous fictional son, Alan Partridge. And I'm sure that Steve Coogan's comic creation would have something politically incorrect to say about the local council's reported plans to differentiate the cost of its parking permits according to a car's length. (His Rover 827 would have fallen well inside the largest 14 ft 7 inch and longer category.)

This was the place that tried to cut down a line of Horse Chestnut trees on the grounds that conkers were a health n' safety hazard. But even by the standards of such previous lunacy, this proposal stands out as something especially daft.

The council's logic - so far as it has any - is not just that longer vehicles take up more parking space, but also that they tend to have higher emissions. It's a point of view that no more than 30 seconds spent with the back section of What Car? could comprehensively de-bunk, not least as the Toyota Prius falls into the longest and most expensive category.

Oh, and even more amusingly, the 12' 7" Land Rover Defender 90 would fall into the shortest and cheapest category, despite putting out 266g/km of CO2 and having a turning circle that would rival a mid-sized supertanker. Compact, eco-friendly urban transportation it is not.

But there's another, more serious point here - a desperate lack of national political leadership. Meddling, revenue-hungry local councils seem determined to introduce all kinds of ad hoc restrictions based on this sort of strange, half-baked criteria. If it's allowed to carry on unchecked then the end result will be close to chaos, with people buying cars to get under different emissions or size targets in different parts of the country, and then falling foul of local legislation when they travel further afield. It's as mad as allowing local councils to unilaterally introduce 17.5 mph speed limits, or to declare that only red cars will be allowed into town on Tuesdays.

Despite the doubters, the motor industry has proved that it's able to play by a set of rules - just look at the number of sub-120 g/km cars that were being readied to meet London's proposed (and recently revoked) new congestion charge limit. What we need is a hard-and-fast set of national rules so that everybody knows where they stand and can make car-buying decisions accordingly.

Of course, one of Norwich's other substantial contributions to British culture was its use as an acronym for sex-starved British squaddies beating the censors when writing home during the second world war: "kNickers Off Ready When I Come Home."

If this sort of madness is allowed to continue unchecked it will be the rest of us getting bent over backwards.