I have posted on this before, tobacco is not just smoking material in a prison it is currency. Even prisoners who do not smoke need tobacco to use as 'cash'. You need a haircut? There will be a prisoner who cuts hair (often one who has been a barber on the outside.) He will be paid in tobacco, 1/2 oz (12.5 g)a hair cut is was the price when I worked in a prison.You want 'porn' mags or pictures to pass the time, you pay in tobacco. Another inmate has had some sweets or food items sent to him and he wants to sell some of it, you pay him in tobacco!
The smoker/non smoker ratio is reversed in prison . On the 'out' only 20% of people smoke , 'inside' less than 20% do not smoke over 80% are smokers.
Smoking only when out on in the exercise yard ? Forget it, now due to staff shortages most prisoners are 'banged up' 23 hours a day only allowed out to collect food and then they return to their cells to eat it.
Outside exercise is 1 hour a WEEK in most jails not 1 hour a day!
Prison staff in the main are against banning smoking as they know it will make their job even more difficult.
When you see prisoners sitting in the canteen eating their meals while chatting to each other in TV shows or films that is a fiction, to make a better story line.You can't get much of a story out of the reality where prisoners are only allowed out a few at a time to collect their food and return to their cells to eat it.