Cyclists are NOT carbon-friendly (whatever that means); a cyclist pedalling away, especially uphill, breathes out more CO2 thab a car and passengers who are sitting relaxed and breathing gently.
That assumes that CO2 is the enemy anyway, and lots of independent scientific opinion - i.e. that which is not funded by Government grants, etc., have the view that CO2 is simply not a factor in climate change.
However, I certainly do think that cyclists should be identifiable in the same way as motorists and answerable for their misdemeanours. Paying a fee, whatever you call it, will fund the issue of licence plates and enable our overworked police to penalise them as easily as they do motorists.
Incidentally, as most traffic penalties have little to do with safety and mostly for revenue generation, why not enforce the £30 on-the-spot fines for cycling on the pavement and jumping red lights, etc? I would be happy to volunteer to collect such fines, on a part-time basis, for a 10% commission!
Ron.