FF has hit the nail on the head here. Janner has been strongly suspected on these charges for many years. The "establishment" clearly obfuscated previous attempts to put him on trial, when his health wasn't an issue.
Its clear what has happened here, because its similar to the Cyril Smith case.
The main reason that these old men have got away with their crimes is because they know where the bodies are buried. Indeed, it now appears that it might literally be true, as there is growing evidence that boys ere abused and the murdered ! If one of these chaps were to be prosecuted, than more names would come out and the foundations of the "establishment" would begin to crumble.
This is one of the reasons why Janner is in the news today, because he was implicated during the trial of 1991 trial of Frank Beck, a local care-home warden.
But Ummmm is correct....a person with dementia would hardly make a credible witness. The CPS's crime here is dragging their feet years ago.