I totally get the argument that people going to prison can pick up more contacts/knowledge and come out to re-offend. I also get that they may seriously mess up their future job prospects.
But what's the alternative? A slap on the wrist? In theory that might make people feel lucky to have been given another change and go straight, but they don't do they? They learn that they're above the law and get worse.
The softly softly approach has to be as bad, or worse, and we - the public - suffer from these people being out on the street as against locked up. What's the cost to the economy from their crimes (including the ones that never get solved, nor do the criminals ever have the money to pay back the damage done) when they're free, as against the cost of keeping them locked up?
Personally, I'd continue to lock people up (which might just stop everyone growing up to think it's okay to do what you want) but look at how people are treated inside a young offenders institute or prison. Why do they get access to drugs and even mobile phones? Why are they able to freely talk about how to commit more crimes - and so on.
While I am all for giving people another chance, you also need people to realise just how much prison might mess up their life - to serve as a deterrent in the first place.
For goodness knows how long, people of all backgrounds have got this message that you can break the law and be fine because most of the time you will.
Naturally, at the same time as doing all of this, you need to be making sure that you're creating a society that gives everyone a fair chance at getting a job, or furthering their education, getting on an apprentice scheme.
Finally, you make it socially unacceptable to be a layabout - and benefits will only cover those who really can't work or have a genuine disability. It's far too tempting (as I found when I left school) to just sit back and get your unemployment or income support. I was surrounded by friends who did just that, and I knew that I didn't want to do it - even though it was easy money. I had aspirations at bettering myself that some people didn't, and nobody was around to convince them otherwise (and this was 1990 so under the last Tory Government).