Oh, yes. They snuck it in on the same boat as "Will nobody think of the children ?".
I remember at the time, a fuckload of numpties who either really didn't get it, or who were just playing to the gallery trying to compare it with banning <something else>.
However they could never surmount the hurdle that <something else> hadn't been proven to harm people who didn't partake in <something else>. Whereas smoking most certainly affected non smokers. Just ask the Castle family.
The real test here is posterity. Even Farage hasn't dared suggest repealing the smoking ban. It's just become part of Britain. Like decimal currency that he also hasn't suggested ditching.
When it was floated, I was working in financial services, so the ironically back of the fag packet calculation was quite informed. However it missed the raising of the pension age and the slight reduction in life expectancy.
There is of course the additional factor of expenses caused by people replacing smoking with vaping etc etc. Although maybe the littering is the same so that's zero-sum.