DJ Chris Evans has impersonated sex predator Jimmy Savile live on air to nearly 10 million listeners.
The Radio 2 Breakfast Show host imitated the disgraced BBC TV star's distinctive delivery, joking: "It sounds like someone else whose name escapes me at the moment - I have no idea who that is."
His producer quickly intervened, saying: "We've never needed to move on more urgently."
It came after the 47-year-old played Sparks' 70s hit This Town Ain't Big Enough For Both Of Us.
He compared the American band's frontman Russell Mael to Jessie J and then implied his own rendition of the 25-year-old's Price Tag singer's voice sounded like Savile's.
The late DJ's 54-year campaign of abuse counted among its victims an eight-year-old boy and seriously ill children.
Over 50 of those who were attacked are seeking compensation from the BBC, the NHS, Savile's estate and other organisations.
Evans has made controversial comments on air before - i n 1996, Radio 1 was forced to apologise after he made tasteless jokes about Holocaust victim Anne Frank.
His Breakfast Show, which he took over from Sir Terry Wogan in 2010, currently boasts an audience of almost 10 million.
BBC2 could not be reached for comment.