According to the retired BBC worker, the Crimewatch host was told that DJs, stars and corporation staff were involved in organised abuse.
But when she tried to get bosses to investigate the alleged ring and other abuse complaints inside the BBC “no one wanted to know”, the former friend said.
Undeterred, Jill is said to have then raised the claims with senior management in the mid-1990s but no investigation took place.
The TV host was shot dead a few years later on the doorstep of her London home. The 37-year-old’s murder remains unsolved.
Her ex-colleague, who asked to remain anonymous, said: “I don’t recall the names of all the stars now and don’t really want to implicate anyone but Jill said they were surprisingly big names.
“I think she was quite shocked when told about images of children and that information on how to join this horrible paedophile ring was freely available.
“Jill said others had complained to her about sexual matters and that some fellow female workmates also claimed they had been groped or assaulted.
“Nothing had been done and there seemed to be a policy of turning a blind eye.