Re: Fair enough, but...
I think you will find that already exists, the legislation. Just needs enforcing.
As for requiring them (of which I am one) to have insurance. It doesn't seem to stop car drivers (of which I am also one) behaving like nutters. Its not entirely a bad idea though. Maybe you need insurance to ride on A roads where risks are higher because of higher speeds. It would be a bit harsh requiring your kid to need insurance to cycle around a residential estate with their mates.