Broadcaster Paul Gambaccini has added to the claims that Sir Jimmy Savile sexually abused schoolchildren, claiming the star used his charity work and ‘imperial personality’ within show business to prevent his private life being exposed.

Speaking ahead of a forthcoming ITV documentary that claims Savile abused schoolgirls during his many years of stardom, Gambaccini said his former Radio 1 colleague played tabloid newspapers “like a Stradivarius” in order to keep the abuse secret.

Exposure: The Other Side of Jimmy Savile, which is due to be screened on Wednesday night, will detail claims from women that the late television personality sexually abused school girls in his Rolls-Royce and at BBC Television Centre. The allegations date back to the 1970s.

Speaking on ITV1’s Daybreak programme this morning, Gambaccini said he had been waiting 30-years for the allegations to come out.

He alleged that at one point Saville was about to be exposed by a tabloid newspaper, but quickly arranged an interview with a rival tabloid which had the effect of stopping the negative article.

Gambaccini went on: “On another occasion, and this cuts to the chase of the whole matter, he was called and he said 'well you could run that story, but if you do there goes the funds that come in to Stoke Mandeville - do you want to be responsible for the drying up of the charity donations'. And they backed down.”

Sir Jimmy had raised millions of pounds over the years for his pet cause, Stoke Mandeville Hospital.

Gambaccini added: “It comes out when he's dead because Jimmy Savile had an imperial personality in show business; I'm not talking about personal life. You just didn't mess with Jim. He was the governor, because after all he had been the first great club DJ, he had been the originator of Top of the Pops presentation, and you just let him have his turf. And none of us were interested in going there because he was away from us. At social occasions we would all be together, but Jim would not be and he had his own life.”

Gambaccini’s revelations come after ITV defended the documentary after a member of Savile’s family condemned the allegations.

An ITV spokesman said: “This documentary is the result of an in-depth investigation into long-standing allegations of serious and widespread sexual misconduct by Sir Jimmy Savile. Because of the very serious nature of the claims made by several interviewees in relation to this, particular care and consideration was of course given to the decision to produce and broadcast this programme.

”The programme takes full account of the fact that Sir Jimmy is not here to defend himself against these claims“.

The defence comes after Roger Foster, Savile’s nephew, said his family were “disgusted and disappointed” that the allegations are being made when he is no longer around to defend himself, adding that he is concerned at the potential damage to his uncle’s charities, as well as Savile’s reputation and legacy.

”I just get so disgusted and disappointed by it. The guy hasn't been dead for a year yet and they're bringing these stories out. It could affect his legacy, his charity work, everything. I'm very sad and disgusted”, he said.

”I just don't understand the motives behind this. I just think it's very, very sad you can say these things after someone's died and the law says you can't defend yourself when you're dead.“

ITV said the programme, presented by former detective Mark Williams-Thomas, features contributions from several women who claim that Sir Jimmy was a sexual predator who sexually assaulted them while they were under-age.

One woman alleges that she was raped by the DJ and another says she was asked to perform a sex act on him.

ITV said one of the contributors explained how she was too frightened to speak out while Sir Jimmy was alive. They said the programme will allege that the broadcaster preyed on teenagers whom he invited to appear on his TV shows.

One 14-year-old girl tells the programme how she met Sir Jimmy at a school in Surrey in 1974 and he assaulted her in his caravan which was parked in the school grounds.

ChildLine founder Esther Rantzen, who worked for the BBC during the 1970s, told the programme that she now believes Sir Jimmy sexually abused under-age girls, after seeing the fresh evidence from their interviews.

”We all blocked our ears to the gossip…We made him into the Jimmy Savile who was untouchable, who nobody could criticise. Jim'll Fix It was for children. He was a sort of God-like figure. Everybody knew of the good that Jimmy did and what he did for children. And these children were powerless“, she said.

The BBC responded to reports that inappropriate behaviour by Sir Jimmy was an “open secret” at the corporation by saying it found no evidence of any misconduct by the broadcaster.

“The BBC has conducted extensive searches of its files to establish whether there is any record of misconduct or allegations of misconduct by Sir Jimmy Savile during his time at the BBC. No such evidence has been found,” it said in a statement.

“Whilst the BBC condemns any behaviour of the type alleged in the strongest terms, in the absence of evidence of any kind found at the BBC that corroborates the allegations that have been made, it is simply not possible for the corporation to take any further action.”

The BBC also explained why an investigation into Sir Jimmy by BBC2's Newsnight was never broadcast.

Newsnight editor Peter Rippon said: “It is absolutely untrue that the Newsnight investigation was dropped for anything other than editorial reasons.

”We have been very clear from the start that the piece was not broadcast because the story we were pursuing could not be substantiated. To say otherwise is false and very damaging to the BBC and individuals. The notion that internal pressure was applied appears to be a malicious rumour.“

Mark Williams-Thomas, a former detective who presents the documentary, told ITV's Daybreak that the alleged victims had not come forward before because they “lived in fear for a very long time”.

He said: “We know that children don't disclose abuse straight away; sometimes that takes a long time, for many, many reasons - their whole life changes, the circumstances change...

“And particularly talking out against Sir Jimmy Savile, who of course was a TV legend, (it is) very difficult to talk out about that, and they have been reassured of some confidence by talking now that he has died.”

But Sir Jimmy's friend, Howard Silverman, defended the TV personality, saying he was a “normal, ordinary guy” and “quite a cleaner-than-clean person”.