PH, What's the point of prison?

By the end of the 19th century, thanks to wise reform and the abandonment of the wilder liberal ideas, the Victorians had arrived at rather a good compromise.

The police deterred crime in cities and countryside, the Churches and the Temperance movement worked constantly to improve morality. Heinous murderers were hanged, so there were very few of them. The municipal reformers sought to clear the slums.

And the declining numbers who committed crimes went to prisons which were austere and harsh but not cruel or chaotic or diseased.

Prisoners had to work. They were kept under strict discipline, they lived in single cells and every moment of their lives was governed by hard rules. They could associate with each other only in very limited circumstances. Food was basic. Heating in winter was minimal. Contact with the outside world was very limited. Tobacco was not allowed (let alone drugs). Remission had to be earned by consistent good behaviour, as did privileges - access to books, visits, letters, better food.
In short, the authorities had the upper hand, all the time. Prison terms were not usually particularly long, but few who had undergone them wished to sample the fare again. Word got out that a spell in prison was to be avoided. People avoided it.

Edit. Some reflections on hanging, and a few general remarks