SIR – People grumble about cyclists without lights but parents cannot buy bicycles with built-in lights.

There would be chaos on the roads if motorists had to rely on fragile plastic lights which break easily and rely on separately fitted batteries which keep running out.

With modern technology lights could be an integral part of a bike and be expected to last for five or ten years without needing replacement parts.

It would be easy nowadays to provide the power without the drag associated with old-fashioned dynamos. Rob Wheway, director, Children’s Play Advisory Service