BBC star presenter Jimmy Savile sexually abused up to 1000 children in the corporation's changing rooms and studios, while staff turned a blind eye, an internal inquiry will reportedly reveal.
Former Court of Appeal judge Dame Janet Smith would say in her report that the true number of victims may never be known, but that Savile's behaviour had been recognised by BBC executives who took no action, The Observer reported.
The newspaper predicted the BBC would be plunged into a major crisis when the review was published, which was expected to happen in February.
The Observer quoted a source close to the inquiry saying: "The numbers are shocking. Many hundreds and potentially up to 1000 people were victims of Savile when he was representing the corporation. The report will ... go right to the heart of how Savile was able to get away with the most heinous of crimes under the very noses of BBC staff for more than 40 years."
Smith's team has sent letters to every member of BBC staff past and present asking whether they had witnessed criminal acts by Savile. The review had also been in contact with more than 1000 witnesses and victims.
In three known cases, one of which involved a BBC cameraman who had since died, Savile carried out his abuse with others connected to the corporation, the review had heard.
The report would express frustration that some of those closest to Savile, or culpable for allowing him to go unchallenged refused to co-operate, The Observer said.
His criminality peaked in the 1960s and 1970s, when he was middle-aged and at the height of his career at the corporation. It continued until the last filming of Top of the Pops in 2006 when at the age of 79 he groped a girl aged between 13 and 16.
Peter Saunders, chief executive of the National Association for People Abused in Childhood, said he found extraordinary and sad "the number of people I have spoken to connected to the BBC, and that is a lot of people, who said: 'Oh yes, we all knew about him.'"
Liz Dux, a lawyer representing 74 of Savile's victims, said she hoped the BBC would respond to Smith's findings by offering further support to victims, who are due to receive limited compensation through a scheme being agreed with the corporation, the National Health Service and the Jimmy Savile Charitable Trust. Those raped by Savile are unlikely to receive more than £50,000 (NZ$100,000) in compensation.
Another report, looking at Savile's abuse within the NHS, had been delayed due to the number of places in which Savile committed crimes.