Oh belt up! A minority of active smokers actually become ill as a result of their habit, the danger posed by ETS must be far less. Nobody is forced to work in pubs which allow smoking, and it's ridiculous to argue that the health of smokers who do choose to work in such places is put at risk by ETS.
Around 20 million adults in the UK choose to smoke. Unless they are illiterate, they are perfectly well aware of the risks associated with smoking. Still, they continue to smoke and should be entitled to do so as long as tobacco remains legal and taxable.
When it comes to pubs, although the business is subject to regulation (quite rightly), the public do not have an automatic right to enter the premises or to be served. This is entirely a matter for the publican, who doesn't have to give any reason why he/she refuses access or service. I'm fairly sure that a publican would be within his rights to ban all non-smokers should he so wish. After all, he is licensed to sell tobacco for consumption on or off the premises.
If you don't like smoky pubs and clubs, don't go in them. The choice is yours.