The HMP Parkhurst on the Isle of Wight, a key prison housing violent offenders, lacks basic levels of safety and decency, indicts an inquiry.
While violence is "endemic," the supervisory staff remain indifferent. Clashes among prisoners are not inquired into, and injuries sustained by them are shrugged away as unexplained.
The conditions are so bad that a disabled prisoner was unable to wash properly for over a year because the staff refused to carry him to the showers. Another disabled prisoner went six months without a shower because of a lack of staff "trained" to push his wheelchair.
There is also widespread abuse of prescription drugs, an official inspection found.
And worse, a group of radical Muslim prisoners were able to spread their extremist message to other inmates.
The Muslim chaplain who offered to set up a teaching group to combat the radicals received "little support" from management.
The category B prison, which holds nearly 500 mostly violent and sexual offenders, is a former military hospital first converted into a prison in the mid-19th century.
The report paints a picture of a dysfunctional institution. Parts of the prison building were dilapidated and litter dumped out of cell windows went uncollected, Telegraph reported.
Chief inspector of prisons Anne Owers said Parkhurst was a "troubled institution" with "substantial shortcomings".
She said relations between staff and management were "exceptionally poor".
Ms Owers said: "In many ways, Parkhurst is a failing prison: prisoners feel unsafe and poorly treated, and neither the environment nor the regime are suited to the role of a modern training prison.
"Exceptionally poor industrial relations also exert a malign influence over an already troubled institution.
"Parkhurst badly needs regional and national support to ensure the restoration of basic levels of safety and decency, together with investment to increase purposeful activity."
Phil Wheatley, director general of the National Offender Management Service, said he accepted the prison had fallen below an acceptable standard.
"Parkhurst now forms part of HMP Isle of Wight, whose Governor has embarked from May 1 this year on a radical programme of change with the help of a new senior management team."
"I am determined that the creation of the new prison and the associated restructuring will deliver the changes required," he said.