This sounds like an extreme over-estimate. Some ISP's, mostly mobile ones, default to blocking "adult material" unless you tell them to turn that off. Some of the larger ISPs are under court order to block some specific other content (Pirate Bay in particular; my old ISP was one of them, my current ISP happily lets me access it, not that I've ever done so other than to see if it's blocked).
Most ISPs block at most a tiny set of sites and personally in 23 years of using UK ISPs I've never "organically" run into those blocks (as in, no site I actually had any interest in accessing has been blocked; I've only seen them when checking whether people were right that a specific site was blocked). And yes, that includes visiting sites with "adult material" without running into any blocks.
I do have a VPN, so it'd take me as long to bypass as it takes me to press one button in my browser address bar, but I only need that to evade IP region/country blocks - never needed it to get around UK filtering.
According to the `considered-18` post linked by a sibling comment:
> It shows that this filter is for this specific host name only [daniel.haxx.se], not for the entire haxx.se domain.
So, even more of a WTF.
That must be one awkward call.
That’s not true. I’ve experienced this once before that I can remember, on https://hackmii.com/ and it doesn’t happen on my home network except on actual scam sites which isn’t a government thing but an ISP feature that can probably be turned off. This is a Vodaphone thing, not a UK thing.
I don’t care that much about this specific site, I guess I just want to complain that they don’t have a way to report false positives which maybe isn’t the best reason to post a comment on an unrelated article but still
In the UK where 20% of the internet is blocked – it's surprising you haven't experienced this before. Call your service provider and tell them you want access to adult material.