The prison was originally built in 1820 and opened as the Surrey House of Correction, Brixton Prison was intended to house 175 prisoners. However, regularly exceeding its capacity supporting over 200 prisoners, overcrowding was an early problem and with its small cells and poor living conditions contributed to its reputation as one of the worst prisons in London (worsened when Brixton become one of the first prisons to introduce treadwheels in 1821).
Conditions for women were especially harsh as newly arrived female inmates were made to spend four months in solitary confinement and, following her introduction into the general prison population, would be required to maintain a condition of silent association. Female inmate were allowed over time to earn privileges, which included limited conversation, payment for labor, the right to receive letters and visitation rights.
Eventually the problem of overcrowding was addressed with the prison expanding to house over 800 prisoners and, in 1853, the British government converted Brixton into a women's correctional facility for women who preferred imprisonment rather than deportation to Australia (although female inmates who had become pregnant were also transferred to Brixton from Millbank Prison).
Conditions in the prison gradually improved during the mid-19th century as a nursery was opened in the prison for children under the age of four and, by 1860, inmates were allowed to keep their children until the end of their prison sentence. Brixton eventually became a military prison from 1882 until 1898 and remains a trial-and-remand prison for London and the Home Counties. Conditions inside the prison today are still grim, due to Crown Immunity, normal health and safety regulations are not binding, when the cell doors shut in the evenings all the wings in the communal areas are overrun with mice and rats. The footings for the treadmill remain and are visible and the former 'hanging ie execution suite' is now an enlarged cell with six beds.