The Dame Janet Smith review, due to be published later this year, has sought testimony from those abused by the late TV presenter in half a century with the BBC.
Dame Janet has called on potential victims, witnesses, people who worked with the TV presenter and senior staff at the time to assist with the investigation.
Those close to the inquiry agree with a newspaper report suggesting Savile may have abused up to 1000 people. Savile, who died in 2011 aged 84, is believed to have been one of the UK's most prolific abusers. It is alleged he abused young people on BBC premises, in hospitals, care homes and a psychiatric hospital.