what are some arguments for keeping the jails in public hands.

2 answers

Many, many criminals are very complex disturbed, pathological and antisocial individuals. There is not a clear understanding how to deal with them. If we can't understand these complex individuals, how would a contract with a private company be structured or supervised?
Recently there was a move in my area to "contract" out the jailing of youthful offenders. This very issue jumped into the forefront, as case after case of inappropriate actions took place in these youth prisons. Currently, it is being "studied", whatever that means.
These sites have more information.

http://news.bbc.co.uk/2/hi/uk_news/7197489.stm

http://scotlandonsunday.scotsman.com/scottishprisons/SNP-plan-to-scrap-private.3287518.jp

http://www.opseu.org/news/Press99/May1699.htm