"In the previous programme it was unclear what came first. But I can very clearly tell you now that he created his television series as a vehicle for his offending,” he told the Radio Times.
"I believe he engineered his programmes within the BBC and Radio Luxembourg in order to gain access to children.
"The classic examples are Top Of The Pops, Savile's Travels, Jim'll Fix It - all of them gave him access to young children. That's why there were so many victims."
Mr Williams-Thomas said he realised just how wide the ramifications of his documentary were when Savile’s family removed the entertainer’s headstone from his grave and dumped it in landfill.
He said: “It was such a significant step. I don’t know why it shocked me but it did. It was a visual image – a message to the public from the family that said: ‘We believe this man was a child abuser.’”
The former policeman said he was uneasy about compensation-seeking lawyers becoming involved in the scandal because people might begin to question the victims’ motives.
He added: “That’s not the case for any of the victims we’ve included in the programme or any of those I’ve spoken to. They don’t want a penny from Savile. They just want the truth to be on record, to be listened to, to be believed.”
Scotland Yard launched an investigation into historic sexual abuse by Savile and others after the ITV documentary was broadcast on October 3.
So far detectives have identified about 300 potential victims and are following up more than 400 lines of inquiry.