THE Advertising Standards Agency is being irresponsible in banning Cycling Scotland's advert showing a cyclist not wearing a helmet and its views are ill-informed ("Watchdog bans television advert showing cyclist without helmet", The Herald, January 29).

The science is irrefutable whether one approaches the issue through physics or through statistical analysis. More than half of all reported brain injuries are the result of a car collision. This is simply because the forces involved in moving cars about are inconsistent with those the human body has evolved to withstand. The forces involved in walking and cycling are conversely, below the threshold at which serious damage can occur, except in exceptional circumstances.

To label cycling as being especially dangerous is going to persuade people to drive instead of cycle, which will greatly increase danger on our roads. It is not that helmets can never prevent injury; it is that there is no more justification for cyclists to wear helmets than motorists or pedestrians.

Quite the contrary, if anyone should wear helmets it is motorists. Motorists think nothing of driving at 70mph on a motorway. But sudden deceleration, even at 30mph, is sufficient to liquidise part of the brain as it collides against the internal bone of the skull. Similarly, pedestrians are particularly vulnerable in car impacts: forces are transmitted through the victim's body, and the head is especially exposed. If a car crashes into you while cycling, at least you have the bike between you. The pedestrian has no such barrier.

It is ironic that in the advert the motorist is driving an open-top vehicle with his head exposed. The vehicle has no roll bars. If the car were to tip over, as often occurs in serious accidents, the top of his head would be mincemeat.

The biggest challenge in this field is changing consciousness. Just as we have finally got people to see the moral wrongs of smoking in public places and around children, we need to bring about a paradigm shift recognising that driving children to school, risking their lives and those of child cyclists is unacceptable, not to mention the effect of traffic pollution on their lungs and the chronically poor levels of physical activity that behaviour engenders.

The Advertising Standards Agency needs to do some research and learn some objectivity. At the cinema recently I saw a sequence of car adverts glamourising speed and power. This is what should be exercising their conscience, not the radically safer alternatives.

Norman Armstrong,

Free Wheel North,

3/1 47 Braeside Street,

Glasgow.