I'm of the opinion that the UK Government has overstepped the mark with its legislation. I agree that smoking should rightfully be restricted in public areas where people have no choice - public transport, for example. However, in the case of bars and pubs, and especially private clubs, I really do think that the decision on whether or not smoking is allowed should rest with the owner of the venue. After all, no-one has a statutory right to be in a bar or pub - you are there at the owner's discretion and if the owner says smoking is allowed, then you don't need to stay if you don't like it.
Interestingly enough, the UK Government exempted the bars of the Houses of Parliament from the legislation saying that the Houses are classed as a Royal Palace (which is true) and therefore don't come under the classification of 'public place' and not obliged to implement the ban there. I'm not sure if they changed their minds about that, but, the fact that they did it in the first place speaks volumes.