And, to summarize the single most important point made there:

No, this is not the UK government's "porn filter", because (1) no such thing actually exists yet and (2) this isn't the same sort of thing as that would be if it did exist -- it's one ISP's opt-in whitelist offered to people who want a way to keep their children "safe".

(I am not defending such whitelists, by the way. But even if there is some day a Great UK Adult Content Filter, this is not what it will be.)