Looking at the policy of the British state regarding prisons, the impression one gets is that the UK population is the most criminal in Europe. The massive increase in the UK prison population, up 82% in the last 30 years, puts England and Wales as the highest imprisonment rate in Western Europe, with Scotland coming in as the third. However it is the definition of criminality that sets the standard. In the UK, those in prison with mental health problems is as high as 80%, prison is the last place for such vulnerable people. A very high proportion of the remaining approximately 20%, are there because of social and economic problems and injustices.
Prisons are not there to take "bad" people out of society and reform them, but are there as instruments of repression, to protect the wealth and power of the cabal of corporate and land owning parasites that control the economic system. The UK state is involved in a massive expansion of prison building, because they see the need to be more repressive to contain the anger and frustration of the ordinary people, they see that anger and frustration as a possible threat to their privileges and power. So it must be contained. More and more legislation, more and more ways of taking people of the street, of closing down opposition. More and more surveillance tracking your every move. More and more prisons to deposit those caught up in their all encompassing dragnet. While a prison stands, nobody is free, the prison shadow hangs over us all.
This PDF from Prison Watch gives greater detail to the march of the UK repressive state.