What / how do they do it then? SNI inspection?
In the case that a blocked site resolved to a Cloudflare IP, it would likely be kicked off of Cloudflare, or geo-blocked for UK users (by Cloudflare).
https://www.ispreview.co.uk/index.php/2025/07/cloudflare-blo...
I remember hearing someone complain on HN of their site getting blocked because it shared an IP with an illegal soccer livestream. I can’t imagine they’re doing this to IP blocks owned by CDNs like Fastly, CloudFlare, or CloudFront though. Or are they? Does this regularly break most of the internet for UK customers?