There have been a few interesting cases of "custom" encrypted solutions being sold to crime groups then compromised by law enforcement.
The thing is, most "normal" crime doesn't rely on comms at all - street and domestic violence, burglary, car theft, etc. Fencing stolen items probably could make use of it. It's only really organized crime. And the UK has an increasing problem with organized crime .. from the top, like the unlawful "fast lane" procurement scheme. And the recent business with MI5 identifying an (extremely overt) Chinese agent.
And a surprising amount of terrorist recruitment gets done in the open. As long as you're not planning specific acts it looks like "free speech".
The thing is, most "normal" crime doesn't rely on comms at all - street and domestic violence, burglary, car theft, etc. Fencing stolen items probably could make use of it. It's only really organized crime. And the UK has an increasing problem with organized crime .. from the top, like the unlawful "fast lane" procurement scheme. And the recent business with MI5 identifying an (extremely overt) Chinese agent.
And a surprising amount of terrorist recruitment gets done in the open. As long as you're not planning specific acts it looks like "free speech".