Some reformers, such as Elizabeth Fry, were unhappy at the aim of the separate system. Reformers wanted prisons to be a place of rehabilitation and offer inmates the chance to change their ways. The separate system, some argued, was able to be used in this way. However, many government officials were concerned punishing wrongdoing and deterring criminal activities rather than rehabilitating criminals.

In the second half of the 19th century, the conditions in Pentonville became a lot harsher. The 1865 Prisons Act focused on dishing out punishment to prisoners rather than reforming prisoners through religion or labour. Sir Edmund Du Cane (Assistant Director of Prisons) promised prisoners: 'hard labour, hard fare and hard board':

Hard labour: physically demanding work for 12 hours each day
Hard fare: boring and plain diet, same food served every day
Hard board: beds made out of wood, instead of hammocks