We live in Portlaoise, which is famous for its prisons. Did you know that Ireland has an extraordinarily high use of imprisonment? ask the Transition-year students of Scoil Chríost Rí, Portlaoise

We were horrified to find that our prison population is drawn disproportionately from disadvantaged areas of our cities. Prison is rarely used against the powerful and privileged, against those who commit white-collar crime. It is the most vulnerable in society who are in prison: the homeless, mentally ill, uneducated and poor.

Twenty-five per cent of Irish prisoners were homeless on committal; 43 per cent had left school by 13. More than 75 per cent of prisoners put into strip cells are mentally ill. Last year 300 people with a mental illness were committed to prison.

So what's the solution? There is a need to improve prison conditions, certainly, but also develop and invest in a range of cost-effective community-based options for low- and medium-risk offenders.

Prison is not working, according to chaplains, prison officers and other caring groups. We like to remember what Nelson Mandela once said: "No one truly knows a nation until one has been inside its jails. A nation should be judged by how it treats not its highest citizens but its lowest ones."