The Nottinghamshire hospital is home to "Angel of Death" Beverley Allitt, who was convicted of attacking 13 children and killing four.
About three-quarters of its 400 patients anyone describing them as "inmates" is instantly corrected by hospital staff have committed "very serious crimes" and are admitted for mental illness or psychopathic disorders.
The rest have "challenging behaviour" and have usually been transferred from other NHS hospitals, but are not criminals.
Patients are detained under the Mental Health Act after doctors certify they need treatment under secure conditions on account of their "dangerous, violent or criminal tendencies".
The hospital costs stg£52 million a year to run, with the care per patient coming to about £2,000 a week.
Just last week, relatives of Allitt's victims criticised the "Butlins lifestyle" enjoyed by the murdering nurse at Rampton.
Allitt, 32, is Britain's worst lone female serial killer and has been diagnosed as suffering a mental disorder.
Chris Taylor, whose baby Liam was Allitt's first victim, told the ITV1 documentary Real Crime last week: "Where she is now is like being at Butlins.
"She should be behind bars. I don't want people to forget how evil she was."
Allitt spent just a week in jail before being moved to the Nottinghamshire hospital, six miles from Retford.
Rampton was opened in 1912 as a state asylum and at its peak in the 1940s housed 1,300 patients.
There are 14 high-security main ward blocks and a further 14 secure "villas" in its 190 acres of landscaped grounds.
Its 1,400 staff include more than 800 nurses, 30 medical staff and 150 professionals such as psychologists, social workers and teachers.
In May 2000, the former head of the Prison Service, Sir Richard Tilt, reviewed security at Britain's three high-security hospitals, Rampton, Broadmoor and Ashworth, and concluded measures could be improved.
He said patients should be randomly tested for illegal drugs and locked in their rooms at night, rather than being free to roam their wards. He also called for random cell searches and for inmates' telephone calls to be recorded.
Rules on safety and security at all three hospitals have since been revised.