Thanks to the bullying of UK PM David Cameron, everyone who signs up for an Internet account is asked "Would you like to keep 'adult content' blocked on this connection?" It's a misleading question.
A more accurate version is "Would you like an unnamed third party company to use a secret, arbitrary, ever-changing blacklist to spy on all your clicks and decide which ones are and are not allowed to get through?"
Like China's Great Firewall, the UK firewall is a patchwork of rules and filters that are opaque to users and regulators. Every ISP uses its own censorship supplier to spy on its customers and decide what they're allowed to see, and they change what is and is not allowed from moment to moment, with no transparency into how, when or why those decisions are being made.
Case in point: at the moment, Virgin Media (whose process for reporting incorrect censorship is so complicated that Ray Corrigan, a computer scientist who teaches and researches at Open University, couldn't figure it out) is blocking access to APPG on Extraordinary Rendition, a site where you can get Parliament's own documents on "extraordinary rendition" (this being the favoured government euphemism for "sending people to other countries to be tortured").
There's no way to know why Virgin blocked this. It seems like just straight up misclassification, rather than political shenanigans (Virgin says the site is serving malware). But that's beside the point -- unaccountable censorship of important political material is no more acceptable if it takes place due to incompetence (or indifference) than due to ideology.
After all, all censorship is ideological, starting from the principle that it's acceptable to censor in the first place, and that "overblocking" is an acceptable cost in the service of censorship.
Virgin Media appear to be blocking the website of the All-Party Parliamentary Group (APPG) on Extraordinary Rendition. As Chair of the group, Andrew Tyrie says, the
"APPG is a Parliamentary body with over sixty members, both Members of the House of Commons and the House of Lords.
You can visit the APPG’s website here"
Except you can't as a Virgin Media customer since you get re-directed to a page saying
Sorry, Web Safe has blocked this site
This site has been blocked by Web Safe because it's listed as having malicious content. It could put your personal and financial information at risk or cause damage to your files.
Find out more about Web Safe Sign in to My Virgin Media to change your Web Safe settings If you don’t think this page should have been blocked, let us know.