I'm a non-smoker. Were I to go to prison, I'd have a slight preference for its being a smoke free environment. I'd have a much much much stronger preference for it being a rape-and-shiv free environment. I've heard very little about the latter and the occasional snicker about it being part of the sentence; I don't put much weight on the government actually being overmuch concerned about the health of non-smoking prison inmates.
Rob Hosking at The National Business Review has it right:
But the move to stub out smoking in prisons is raw politics, of course. The idea seems to be to get the government attacked by those who would stick up for prisoners’ rights, and thus make the government look tough on crims.
There is nothing like being attacked by the Howard League for Penal Reform, or some other body made up largely of criminal lawyers, to make a politician look good.