NHS inspectors have called for Broadmoor Hospital to be re-developed.
Broadmoor Hospital was built in 1863
In a damning report, the Commission for Health Improvement said conditions at the high security hospital fail to meet even basic standards.
It said the "overwhelming majority" of wards at the Berkshire facility were "totally unfit for their purpose".
The hospital, which was built in 1863, houses some of Britain's most notorious criminals, including the Yorkshire Ripper, Peter Sutcliffe.
The findings follow an investigation by CHI into the West London Mental Health Trust, which runs Broadmoor.
It found that conditions at the hospital fell below basic standards of dignity, privacy and cleanliness.
It said the hospital "cannot be considered an appropriate, humane environment for modern mental healthcare delivery".
Inspectors praised the efforts of staff to try to provide high quality care to the 400 patients at the hospital.
However, they suggested that poor conditions made their jobs impossible.
In addition, they warned that many staff were not keeping up-to-date with courses on
violence and aggression management.
They said this created a potentially serious risk for staff and patients.
The Commission for Health Improvement suggested care at Broadmoor could only get better if the facilities improved.
"It is difficult to see, in spite of the endeavours of staff at all levels, how healthcare of a sufficiently high standard can be provided in many of the current buildings, which are poorly configured, decorated an maintained and lacking in basic standards of dignity, privacy, cleanliness and amenities," the report said.
Jocelyn Cornwell, acting chief executive of CHI, suggested that the only solution was to redevelop the hospital.
"Much of the high secure services of West London Mental Health NHS Trust are provided in poor working environments.
"The trust must continue to progress the business case to redevelop Broadmoor
Dr Julie Hollyman, chief executive of West London Mental Health NHS Trust,
welcomed the report.
"The report is critical of buildings on the Broadmoor site, many of which date back to the original build of 1863 and can no longer be considered
appropriate for modern psychiatric care.
"This will hardly come as a surprise to anyone but as CHI make it clear plans
were already under way to redevelop the site.
"Significant funding has already gone into upgrading security, a new sports
and visitor facility to address physical health issues and construction work has
already begun on a new unit for the treatment of personality disorders.
"A business case for the redevelopment of the remaining buildings is being
Marjorie Wallace, chief executive of the mental health charity SANE, said: "Having been a very regular visitor to Broadmoor over the years, I am shocked that the conditions on the wards are still so disgraceful.
"The scandal is that despite all the pledges, there are still few alternatives for those people, particularly the women, who do not need that level of security and confinement.
"A place in Broadmoor costs £100,000 a year. Given such an investment of taxpayers¿ money, the least we should be able to provide are humane and tolerable conditions."