Considering All UK Internet user have to use UK ISP one way or another, why not have a list of banned site and force ISP to block it? It really should be the UK side responsibility and not an US company to have to block it. And considering how UK is cosy up to China they might as well ask the Chinese to help them setting up Great Firewall.

I really do think there should be a simple Cloudflare like services that ban all UK user as a form of protest. I say Cloudflare like and not Cloudflare because I am not sure if they are willing to risk supporting this feature.