Depending on how "user" is defined (and interpreted by the courts) it might be possible to avoid some of these regulations by splitting a service into two: the first would accept encrypted blobs from its users, and the second would allow its users to search for blobs based on a substring (i.e. a recipient header).

Of course it would be easy to prove to the court that there was some sort of conspiracy going on, but it's not clear which service would be breaking which regulation, especially if there were "unofficial" third party apps for creating and decoding the blobs from and into plaintext, which the "official" apps didn't do.

> An access restriction order can also require app stores to remove an app from being downloadable by UK users.

Somehow I think that the government won't be satisfied to just have E2EE chat apps removed from app stores, they'll also want them to not be side-loadable onto phones, or installable on laptops.

It's only a matter of time before Apple’s OCSP system and Microsoft's TPM requirements get conscripted into enforcing these restrictions too.