Prison will cost us £12 billion over the term of this Parliament.

The Prison population in our fine country has hit the record-breaking figure of 85,000.
The average cost of keeping a person in prison for a year is £28,486. 
I make that an annual cost of £2,421,310,000 for the whole lot.
A cool £2.4 billion of our hard earned earned taxpayers' money every year. It wouldn't matter so much if prison worked, but it doesn't.

"2.4 billion in not a lot for a banker, but is a significant sum for us ordinary people.1.6% of our budget deficit.

Now we cannot empty the prisons overnight and save that 1.6%, but we can do things more efficiently and more humanely.
First and foremost, prison should be for people who are a real danger to society, or who will not comply with community payback orders.
Second, and also foremost, we need to start moving towards making Britain a place with better income equality, since Wilkinson and Pickett show that more income equality = less criminal behaviour (e.g. drug abuse) and a lower rate of imprisonment.

In the coming years of austerity, we need to make all the savings we can. Prison policy is a good place to start. But it is going to be difficult, because of the vengeful, emotional outpourings of the Mordoch/Daily Mail axis. So the question is, not can we afford to send people to prison, but can we afford the Daily Mail?