The Transport Secretary, Sir George Young (distinctly leporid in appearance, down to the ears), explained it all yesterday. He showed how the combination of heavy traffic and high speeds leads eventually to "bunching" and paradoxically longer journey times. And he revealed that the most heavily used section of the infamous M25 (built, readers will remember, to render congestion in the London area a thing of the past) is to test a system of variable speed limits, activated by sensors reading traffic flow in the motorway's lanes. The more cars there are, the lower the speed limit.
Only one other element is necessary for this scheme to work, says Sir George, and that is the public's co-operation. Ah well, there was bound to be a catch. We all know how fanatical many motorway drivers are about obeying the rules. A short spin on the M1 or the M62 will indicate just how well we keep our distance, observe the speed limit and use the outside lanes for overtaking only. George - it's a jungle out there.
Fortunately the minister is not really relying on our voluntary co-operation at all. He was just being nice. Cameras linked to the speed signals will snap the offending hares, and letters will then arrive at their lairs giving notice of pounds 40 fines and three penalty points.
All of which prompts a couple of subversive little thoughts. The first of them is that such speed limits could be applied to many other highways with the effect, assuming Sir George's hypothesis to be correct, of substantially diminishing the need for a massive and disfiguring road building programme.
And second, despite the howlings of the AA and RAC (Britain's equivalents of the National Rifle Association in America) about civil liberties, could not these cameras be used far more widely to penalise speeding and appalling driving on all roads, at all times? Just think, that idiot in the Ford Probe or the Honda Prelude who cut you up last week could find himself laughing on the other side of his face. We tortoises could come out of our shells.