He won't make the 40 years, unlike Ian Brady, who was deemed to be mad, Huntley is just evil, and sooner or later he'll meet the wrong sort of cellmate, it's pretty common knowledge that screws can turn a blind eye to guys like him getting a hiding, no doubt he'll come into contact with someone else who isn't going to be out anytime soon, and voila, one dead huntley.
Anybody who does him in, will be pretty much a hero inside, even if the courts don't agree.