An unhealthily high percentage of prisoners smoke. Reliable figures aren't available, but it might be as many as one in four, or even one in three. We have seen some people claim the figure is as high as 80%. It isn't.
The prisoners smoke rolls ups. Every week they buy their tobacco (called "burn") and cigarette papers.The rules are simple: no smoking in enclosed public places, like dining rooms or games rooms. No smoking during visits. Smoking in cells is permitted unless you share a cell with a non-smoker. Then it isn't.
The rules are often broken. There just aren't enough officers to catch rule-breakers. Having a crafty fag is not seen as a breach of prison discipline.
A blanket ban won't work. Plenty of officers smoke. They have better things to do than track down secret smokers.
But a High Court judge has decided that there should be a blanket ban. Prisons must be treated like public places. The Ministry of Justice has been given permission to appeal.
Meanwhile, somewhere in one of Britain's jails a prisoner is drawing on a roll up and leafing through the Human Rights Act.
Steve Dagworthy is senior consultant at Prison Consultants. He previously served half a six-year jail sentence for what was described in court as a £3m Ponzi scheme.
Prison Consultants can be contacted for a free confidential discussion on: +44 (0) 20 7717 5564.