What made the UK govt. change it's position on cigarettes?

Question

there was a time when it was widely accepted that it was in the pockets of cigarette companies (remember Blair and the F1 tobacco advertising fiasco). so what changed?

Answer 1

Blair was.  The machinery of government was not, and neither was the NHS.  The Mandarins started quantifying the cost of smoking, and were for once able to persuade the politicians that the figures made sense - I'm glad to say.