Violence against staff has increased at a prison subject to riots last summer, an inspection report has said.
Chief inspector of prisons, Peter Clarke, said there had been a “shocking worsening in standards” at HMP Featherstone, near Wolverhampton.
The unannounced October inspection was held two months after inmates started fires during a week-long disturbance at the prison.
The decline is not acceptable but reflects pressures, a spokesman said.
The Category C prison, which holds 650 men, was last inspected by the HM Inspectorate of Prisons in 2013, when it received a positive report and scored highly in two out of three areas.
The latest report found a “sharp decline” in three out of four areas, with safety assessed as “poor”.
The unannounced inspection found levels of violence, particularly against staff, had increased.
Two thirds of prisoners said it was easy to obtain drugs, with a fifth admitting they had developed a drug problem while inside.
Some prisoners chose to stay in their cells 24 hours a day to escape the violence of other prisoners and a number were “living in fear” because of money they owed, inspectors found.
They also reported that a segregation unit damaged during last year’s riots was still out of action, some prisoner unrest was going unreported and staff shortages meant the prison was unable to operate to its full potential.
“The backdrop to the decline at Featherstone was clear evidence of poor industrial relations, staff shortages and some significant prisoner unrest,” Mr Clarke said.
The report noted the quality of teaching inside the prison was good.
Michael Spurr, chief executive of the National Offender Management Service, said he was convinced the Featherstone governor could turn its fortunes around.
“The deterioration in performance at Featherstone isn’t acceptable, but reflects the real pressures which the system has faced over the last few years,” he said.
“The Government has set out a clear plan for reform in the Prison and Courts Bill laid before Parliament last week, including investing more than £100m to provide 2,500 additional prison staff.”