My turn to apologise - I must have been editing when you posted - your post wasn't there when I added a bit.
Whole life tariffs were challenged in,
IIRC, in court (under Human Rights legislation - again
IIRc).
But Saracen has also answered, and as he says, in some cases guilt can be established absolutely, beyond a shadow of doubt.
Edit -
IIRC (I haven't looked it up) the ECHR stated that Ministers could not impose a whole life tariff - that was the prerogative of the Judiciary - but I think it also said that that the possibility of parole must never be ruled out. But IANAL so I'm not sure how that has been implemented.
But this has moved a long way from the original moral dilemma over listening to music written by a criminal - which has even more relevance since the conviction of Rolf Harris.