A report into five decades of allegations against Jimmy Savile has found the late BBC presenter spent "every waking minute" of his life thinking about abusing children.
It found the British star, who died in October 2011 at 84, had almost certainly abused more than 450 people.
"He spent every minute of every waking day thinking about it, whenever an opportunity came along he has taken it," leading investigator Detective Superintendant David Gray said.
"He is programmed to think and act in that way.
"He only picked the most vulnerable, the ones least likely to speak out against him."
Savile's alleged victims ranged in age from eight to 47 and 82 percent of them were female.
Most of them were aged 13 to 16, and he abused a total of 18 girls and 10 boys under the age of 10.
The head of the Savile inquiry, Commander Peter Spindler, said Savile had "groomed a nation" using his celebrity status and charity work.
"He was an opportunist who at time also groomed children or young people as part of his offending," Commander Spindler said.
"Basically this whole sordid affair has shown the tragic consequences of when vulnerability collides with power.
"He exploited his celebrity status, he traded on the currency of celebrity, to get himself almost unprecedented access to our institutions, to our hospitals, to our schools, and there he took advantage of the most vulnerable in society."
The report found there was no evidence Savile was part of a paedophile ring, although he may have been involved with an "informal network".
Detectives were contacted about 50 cases of abuse at 14 medical institutions, including hospitals, psychiatric units and a hospice according to the joint report by Scotland Yard and anti-child abuse charity NSPCC.
Four alleged offences took place at psychiatric hospitals and Savile was said to have abused a seriously ill teenager at a hospice.
The report said hospitals took Savile "at face value" because of his growing celebrity status, allowing him access to vulnerable children and adults.
The majority of the National Health Scheme (NHS) institutions involved have launched investigations into abuse allegations and the Department of Health is conducting a separate investigation.
At Broadmoor psychiatric hospital, where Savile allegedly committed an offence in 1991, the star had his own set of keys to the hospital.
At Stoke Mandeville Hospital in Aylesbury, where Savile was a fundraiser and volunteer and had an office and a flat, there were 22 reported cases of abuse by the celebrity between 1965 and 1988. There were also 16 reported cases of abuse at Leeds General Infirmary, where Savile was a porter between 1965 and 1995.
Another victim was allegedly abused at St James' Teaching Hospital and one reported case took place at the famous children's hospital Great Ormond Street in 1971.
Source: AAP, The Telegraph
Author: Alexandra Pleffer, Approving Editor: Fiona Willan