I find it bizarre that x isn't already blocked in Britain given that it's full of porn, and seemingly doesn't do any of the required proof of age checks required by every other porn website under current UK legislation.
Explains why hundreds of Mastodon servers immediately vanished (or they would be fined under the OSA) and have relocated to Japan, where it is already infested with CP with zero moderation.
EDIT: Unfortunately, some here continue to deny this and it's widely known that Mastodon (and the top servers) have been infested with CP and it is still big in Japan [0][1] for years.
Excluding the default instance, the top 3 Mastodon servers (Pawoo, baragg (d_o_t) net, and mstdn (d-o-t) jp) are the biggest and have tons of CSAM.
We don't actually really have the ability to hard block stuff. ISPs can be subject to court orders individually but the costs of implementation are bourne by the third-party or government so they don't like doing it. Best case you get the top 5 ISPs to block it because they already have the infrastructure in place, the smaller ones don't though.
Funny enough, based on my observation, X (formerly know as Twitter) is more likely to ban/shadowban normal users who has weak engagements than algorithm-optimized bots.
A lot of bots are posting pornographic content or selling illegal items on that platform. And since many of the bots are "verified", it is harder to filter them out completely. The whole thing is a mess at this point.