Re: Wow @Danny 5
They don't have to control encryption as such.
Before I go on, this is just a thought experiment, OK. I'm not actually suggesting the following.
It would be perfectly possible for ISPs to block everything by default and whitelist allowed services, and then use DPI to see whether the allowed services were being subverted to tunnel encrypted traffic. That would mean as soon as you put traffic that was not allowed down your link, it would be quenched.
They would also have to make sure that non-IP data circuits (dark fibre etc.) services out of the country were also banned. That would just leave bi-directional satellite services and point-to-point microwave/wireless across national boundaries (like the Northern Ireland border with Eire) to worry about.
Mind you, the Internet in the UK would then bear no resemblance to what it looks like at the moment, and it would look more restrictive than China.
Unfortunately, there is something in the Home Office that seems to make seemingly ordinary cabinet ministers and MPs adopt completely stupid ideas once they become Home Secretary. And we now have an ex-Home Secretary as PM, and a new one with the same ideas.
We're doomed, I say!