The hour-long Panorama programme entitled Jimmy Savile - What the BBC Knew, due to air tonight, features newly disclosed emails and interviews, which will raise fresh questions over the role of BBC bosses in the decision to drop the Newsnight exposé of Savile.
The BBC and Newsnight editor Peter Rippon have always maintained that the investigation was dropped purely for editorial reasons as the team had found "insufficient evidence" to substantiate the report.
Rippon has maintained that there was not interference from above in his decision.
But Panorama will claim that Rippon told colleagues that he could not broadcast the film "if the bosses aren't happy".
The programme will also allege that George Entwistle, at the time the director of BBC Vision, was told he "might have to change the Christmas schedules" if the Newsnight film went ahead as it would clash with tribute programmes to Savile.
Entwistle, now the BBC director general, has always maintained that he played no part in the decision to drop the Newsnight film.
Liz MacKean, a Newsnight reporter, told Panorama that Rippon had given the go-ahead for the film to be shown, but had an "abrupt change" of heart and appeared be "under pressure" from above.
"All I can say is that it was an abrupt change in tone from, you know, one day 'excellent, let's prepare to get this thing on air' to 'hold on'," she told the programme.
She added: "I was very unhappy the story didn't run because I felt we'd spoken to people who collectively deserved to be heard and they weren't heard and I thought that was a failing... I felt very much that I'd let them down."
MacKean also expressed concern over the way in which the decision to drop the report has since been portrayed by the BBC.
The BBC has said the report was about Surrey Police's investigation of the Savile claims, but MacKean says the team were actually attempting to expose the sexual abuse allegations against the TV star.
Speaking to Panorama, she said: "Ever since the decision was taken to shelve our story I've not been happy with the public statements made by the BBC. I think they're very misleading about the nature of the investigation we were doing.
"The story we were investigating was very clear cut. It was about Jimmy Savile being a paedophile and using his status as a charity fundraiser and television presenter to get access to places where there were vulnerable teenage girls he could abuse."
Meirion Jones, the Newsnight producer behind the investigation that was dropped last December, told Panorama that he had warned Rippon that the BBC was at risk of being accused of a cover-up.
In an email sent to Rippon on December 7, 2011, Jones wrote: "I was sure the story would come out one way or another and... the BBC would be accused of a cover-up."
The BBC says that it will not comment while its own investigation into the decision to drop the investigation is conducted.
But last night, the BBC also denied a report in the Daily Mail that Rippon had quit as Newsnight chief.
A BBC spokesman said: "Newsnight editor Peter Rippon has not resigned."
Former Top of the Pops and Jim'll Fix It host Savile died in October 2011, aged 84. But after allegations of sexual abuse against young girls by him were aired in an ITV documentary on October 3, the police launched a formal criminal enquiry, called Operation Yewtree.
Officers are now pursuing in excess of 400 lines of enquiry and have identified over 200 potential victims over a 40-year period.
There have also been questions over the BBC's handling of the scandal, after it emerged that the Newsnight report was axed by the BBC last December. In the same month, tribute programmes to the late Savile were aired by the corporation.
Tomorrow (October 23), new BBC boss Entwistle will appear before MPs on Commons culture, media and sport select committee to answer some tough questions about the BBC and Savile.
He has also launched two investigations. Former High Court judge Dame Janet Smith will examine the culture of the BBC during the years that Savile worked there.
The other investigation, led by ex-Sky News boss Nick Pollard, will look at the decision to drop the Newsnight report.
Responding to Panorama's report, a BBC spokesman said: "The BBC has confirmed it has launched an independent review led by former head of Sky News, Nick Pollard, which will cover these questions. It would not be appropriate to comment further until this has been concluded."
Panorama: Jimmy Savile - What the BBC Knew will air on BBC One tonight (October 22) at 10.35pm.
