The smear is here:
> "If you look at what David Cameron says or what (former culture and media Secretary) Maria Miller says and you swap Clarkson for Savile, you get this: David Cameron is effectively saying that Savile's a real talent, Maria Miller saying Savile will be Savile," the source was quoted as saying.
"you swap Clarkson for Savile" is the problem, as it would be if it said "you swap anybody for Savile". I'll give you an example:
> "If you look at what David Cameron says or what (former culture and media Secretary) Maria Miller says and you swap Attenborough for Savile, you get this: David Cameron is effectively saying that Attenborough's a real talent, Maria Miller saying Attenborough will be Attenborough," the source was quoted as saying.
In suggesting that you could swap Clarkson for Savile, the suggestion is that they are comparable. That's the smear.