By all means argue for speed cameras and even speed limits, if you wish. Being a masochist is a trait open to all. But please do not peddle pseudo-science by claiming that they have anything to do with road safety.

Speed limits apply to aircraft, railways, boats and even fairground rides but they are invariably set by engineers, and for very good reasons.

Road limits are set by politicians and the national speed limit was brought in virtually overnight almost single-handedly by a Transport Minister whose name soon entered obscurity.

Imagine driving some of the country's – and the world's – fastest vehicles on Britain's roads entirely devoid of national speed limits. I had that good fortune under tuition from some of England's finest driving instructors.

Being urged to travel at up to twice today's motorway limit never caused me disquiet. Speed per se is not the problem: if it was, we would never have had passenger-carrying Pendolino trains, Concorde or hydrofoils.

The problem is solely one of attitude. To assess a good driver needs a protracted test with an expert. To assess a poor driver, you need only to watch how they barge out of shops without thought for others or observe how they handle a supermarket trolley around crowded aisles.

Incidentally, the last time I checked, there were more than 100 models available to British motorists capable of achieving twice our motorway limit. And if you care for driving on the wrong side of the road, you are free to legally use this speed in parts of Germany.

As Ralph Nader might have said, some people are unsafe at any speed.

Anthony G Phillips Salisbury Wiltshire