I'd bring in hard labour in prisons. Strip all their TV's, playstations, Facebook access, and comfortable cells and make the cells like those in America with just an uncomfortable bed with one open wall of bars only. If I came to power, they'd work 7 days a week, 12 hours a day doing constructive work that the government could sell to make money to help pay our debts and reduce the burden on law abiding taxpayers.
Prisons are like holiday camps, so they become institutionalised very easily, and often go out and commit crime immediately because they actually want to get back in!
They can't lose, if they get away with the crimes, they make money, and if they get caught, it's back to Butlins!
Prisons should be cold, uncomfortable, boring and blo*dy hard work if they are to act as a deterent.