No Cigarettes have an incredibly low price elasticity of demand so if they increase in price by 5% the decrease in quantity demanded will be 1-2% at best.
What you would be assuming is that there is perfect correlation between price and quantity demanded across all products. However cigarettes are addictive so though they can be considered a luxury they are often treated as a necessity, especially since those most addicted to them are the largest consumers and have the least will to quit.
Tobacco duty currently brings in £7.1 billion for the government far outstripping the cost of them to the NHS massively.
More smokers god-damn-it.
The problem that the government has primarily is that the profits that can be made from smuggling are starting to make smuggling very attractive. even still the government will still have greater tax revenues.
And that idea of saving £10 million a year for smokers who have breaks is BS. because that's a simple mathmatic trick the media love to use to exaggerate the truth. Cumulative amount of time spent on smoking breaks * average wage/ hour= money lost. Which is just a plain logical fallacy.
On balnce an increase in taxes on cigarettes will increase smuggling however will secure greater revenues for the government.