Earlier quoted context omitted.
The technology bit doesn't really matter though. The real problem is that the legislation would bring the power to prosecute people who use them or use it against them. The security services aren't having any of that shit because it puts their position at risk both from the front-facing side and recommendations and guidance issued and from their own operations.
The power to prosecute and the actual ability to prosecute are two different things. They currently can't prosecute CSAM offences nor piracy due to capacity. It won't happen.
Force ISPs to log all connections and make ISP customers accountable for their traffic, like they are in Germany for example. If you detect an IP to be used for a VPN, ask every ISP to disclose al customers who interacted with it and issue them a ticket. Three tickets and you're denied internet service for two years.
I think this would scare most people off.