Naomi - banning smoking would not work - just as banning illegal drugs does not mean that we have no drug problem in this country. The only thing that they can do is make it more and more difficult for smokers - by taxing it, by making it antisocial, by saying where you can't smoke etc, which is what they are doing very effectively.
10 years ago, a normal meeting of 20 people would have seen at least half of them smoking. That has changed dramatically now and only 10-20% of people smoke (this is purely me experience and people I speak to - I don;t have time to research the actual facts, but I am pretty certain that the number of people smoking has dropped significantly).