Public interest in prison conditions and the treatment of prisoners grew during the later 18th century.
One of those who promoted this interest was John Howard, who during his lifetime conducted an extensive tour and study of prisons in Britain and on the continent.
In 1774 his evidence to a House of Commons committee led to two Acts which aimed to improve conditions in gaols. His published writings on the subject were widely read and his detailed accounts of inhumane conditions caused dismay.
He advocated a system of state-controlled prisons in which the regime was tough, but the environment healthy. In 1779 the Penitentiary Act authorised the construction of two prisons in accordance with his own theories.
He advocated a regime of solitary confinement, hard labour and religious instruction. The objective of imprisonment, he believed, was reform and rehabilitation, not just punishment.
Though the plans set out in the Penitentiary Act were never carried out, Howard's ideas and proposals were taken up by others.
In 1785 Sir George Onesiphorus Paul, a Gloucestershire gentleman and magistrate, secured an Act of Parliament for building a new gaol at Gloucester.
The completed prison building was regarded as a model of its kind, incorporating individual cells, separation of different classes of prisoner, medical care, exercise facilities and religious instruction.
Over the next 40 years similar initiatives were pursued in many other counties. Local Acts of Parliament were obtained allowing magistrates to build imposing new prisons in their respective counties.