It's going to be interesting to see how this plays with voters at the next election. Politicians think this censorship is a vote-winner, presumably because on the doorstep voters are unlikely to talk about their love of porn. Yet in online spaces, this policy seems wildly unpopular - especially with the high profile leaks of age validation services' user data; the government's legal battles with Wikipedia; Steam's demand for credit cards (debit cards are more common in the UK); and sites leaving the UK market all together.
I suppose we'll get to see whose polling is more accurate at the next election.