It didn't take long for the militant motorists' lobby to get into gear to attack the Government's proposal to reduce the national speed limit from 60mph to 50mph.

To lop 10 mph off the speed limit on country lanes, apparently, is tantamount to declaring a fascist dictatorship. “These corporate Nazi New Labour bastards are intent on turning law-abiding citizens into criminals,” began one of hundreds of angry posts on the website of a prominent motorists' pressure group yesterday - before, bizarrely, imploring his fellow petrolheads to vote for the British National Party.

That the leaders of the motorists' lobby are not quite the defenders of liberty they often profess to be is obvious from reading their output over the years. They have never been slow to demand the prosecution of cyclists, jaywalking pedestrians and motorists who drive too slowly or in any other fashion that impedes their progress.

The assertion that tighter motoring law is tantamount to dictatorship is further confused by a paradox. The world's most illiberal regimes happen to have some of the most anarchic and dangerous of roads, while the most liberal nations tend to have the strictest traffic enforcement and safest roads. For all the conspiracy theories, Morgan Tsvangirai now says that the car crash that tragically killed his wife on Friday was an accident. It shouldn't come as a surprise: reporters who have used the road between Harare and Beitbridge paint a terrifying picture of speeding, overloaded lorries and complete lawlessness - this in a country where if you criticise the President you can expect a rapid visit from Robert Mugabe's thugs.

Drive through the dope-smoking, legal-brothel-ridden Netherlands, on the other hand, and you will find an enthusiasm for speed cameras second only to Britain's.

I am not surprised by the ramblings of the militant motorists' lobby, but I am disappointed by the Conservatives' kneejerk opposition to what is the most sensible proposal to come out of the Government in months. Condemning the idea of a nationwide 50mph limit, Theresa Villiers, the Shadow Transport Secretary, complained that a lower national speed limit would “hit everyone, including the safest and most responsible drivers”, and suggested that speed limits be left to local authorities.

Ms Villiers doesn't understand the problem. Local authorities would love to reduce speed limits on a great number of roads, but they are hampered by bureaucracy. Whenever they want to designate a limit on a rural road lower than the default 60mph they must justify it through accident statistics. It may be obvious that motorists are driving too fast on a stretch of road, but a council must wait for the required number of people to be killed or injured before it can take any action. And even when, finally, sufficient coffins have been filled to justify a speed limit on a rural road, it remains legal to drive along surrounding lanes at 60mph, giving reckless motorists an incentive to divert on to even more dangerous rat-runs.

The Government wants to turn this mad situation around, so that highways authorities would start off with a lower national limit. They could then apply to raise the speed limit on stretches of road where they can prove it is safe to do so. Result: a vastly more logical system.

The only problem is that the proposal does not go far enough. Many country roads are no more than cart tracks covered with tarmac, where 50mph is still far too fast. They never were, and are not now, principally facilities for motorists. They are there to be used by cyclists, horseriders and pedestrians, too.

How about this proposal? Any rural road that does not have white lines painted down the middle - a visual symbol that would obviate the need for a mass of speed-limit signs - should be subject to a blanket limit of 30mph. This would be the same as the blanket limit that applies on urban roads with regularly placed lampposts. Single carriageway roads that do have white lines painted down the middle could be subject to a blanket limit of 40mph and dual carriageways to 60mph. All these limits could be raised where appropriate.

Obviously, as some critics of the Government's proposals argue, speed isn't the only hazard on the roads. They should never be policed by speed cameras alone and there is plenty of scope for saving lives through better road design. It is also true, as the Conservatives argue, that the large number of unlicensed, uninsured motorists need to be tackled with urgency. But a logical system of speed limits is a good starting point for a road safety policy; that there are other problems on the road is no excuse for not having such a system.

Until 2001 governments could brush off demands for road safety measures on the ground that Britain had the safest roads in the world and therefore we couldn't be doing too much wrong. Now we are third, not because our roads have become more dangerous but because Sweden and the Netherlands have made more progress than we have. To want to emulate those countries is not the mark of a fascist dictatorship; it is a mark of civilisation.

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