The accusations, which range from rape to indecency, are claimed to have occurred during the height of his fame on girls as young as 13.
Two of the women featured in the ITV show even allege he gave them money, cigarettes, records and spots in the audience of his shows in return for 'sexual favours'.
Savile had already been the subject of a two-month sex pest investigation by reporters from BBC's Newsnightwho launched a probe into allegations about inappropriate behaviour by the Jim'll Fix It legend towards schoolgirls.
Now in an ITV programme, set to be screened on Wednesday, between five and 10 women claim he was a sexual predator who took advantage of their vulnerablility.
It is claimed the assaults occurred in public places including hospitals, schools and the BBC studios where the children’s TV presenter recorded his family shows.
A source who worked with the investigation team told the Evening Standard the show contains 'shocking material that really lifts the lid on the icon' and 'goes beyond anybody’s comprehension' of what Savile was capable of.
The flamboyant star, who died aged 84 last October, fronted road safety campaign Clunk Click and presented Jim’ll Fix It, which ran until the mid-Eighties.
He also presented the first edition of Top of the Pops in 1964 and the last one in 2006.
Some of those who contributed to the documentary are believed to be former pupils of a school in Surrey, where Savile was a regular visitor.
In 2007 Surrey Police received a complaint from a woman who said she was indecently assaulted by Savile in the Seventies.
The allegation was investigated but no further action taken.
The documentary — Exposure: The Other Side Of Jimmy — took 12 months to make and the final edit was being done today.
At least two of the alleged victims have waived their rights to anonymity.
The source added: 'These are women who were abused as children.
'They tell how it has destroyed and devastated their lives. It affects them to this day.
'Most of them have not told this story before.
'It is the first time they have spoken in detail about everything. It’s explosive stuff.'
Family and friends of Sir Jimmy Savile have slammed the documentary condemning it as 'digging up dirt' as it was impossible for the star to defend any claims.
Sir Jimmy's niece Amanda McKenna, of Leeds, West Yorkshire, said: 'The documentary makers should be ashamed of themselves cashing in on a man who is dead and cannot defend himself.'
His nephew, Roger Foster, added: 'It just to me seems a terribly one-sided programme. How can anybody defend themselves if they are not here to do that.'
Leeds hairdresser Howard Silverman, pals with Sir Jimmy for 40 years, also hit out at the programme which screens at 11.10pm on Wednesday on ITV 1.
He said: 'They are simply digging up dirt. The worst thing is that if it was true the papers would have had a field day over the years with all the allegations Jim had to face, none of which were ever proved to be true.
'We all had fun when we were young but none of it was ever with under-age girls. I was a very good friend of Jimmy's and can assure everyone that this is untrue. He cannot defend himself as he is dead.'
A statement on behalf of the trustees of the Jimmy Savile Charitable Trust added the documentary could taint their effors. It read: 'The publication of such grave allegations may affect the charitable trust, which supports so many good causes.'
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