I'm not sure. I'd be interested to hear Don Head's point of view on whether or not he has seen an impact from the ban or a change in the presence of drugs in institutions after the tobacco ban. I would suggest that it has probably not changed all that much. As I said, a chocolate bar or a bag of potato chips is currency within the prison system. So are knives, by the way.
On October 4th, 2011. See this statement in context.