‘A society is measured by the treatment of its prisoners,’ Winston Churchill said. Last year, in England and Wales, every three and a half days a prisoner killed themselves. What does this say about our society?

Perhaps you think: why should we care – aren’t there better things to worry about than criminals committing suicide? But the suicide rate in prisons is actually, surprisingly, a measure of the safety of society at large, because those who kill themselves in their cells represent the tip of an iceberg of despair within the prison population.