That's actually pretty good. If wiretapping gets publicly discussed by your government the representatives you have voted for will more easily be able to speak on your behalf. A politician must be able to state they want to implement nationwide wiretapping, and the voters must then be able to laugh at them and not elect them ever again.
Actually it wouldn't be to hard. Make it illegal to provide a certain service and then force the providers and the app stores to region lock the software or face fines. You have now stopped the majority of people from using encryption. The only people who are going to bother side loading a chat app are the same people who would use GPG anyway. I do wonder what this means for HTTPS? Websites will no longer be allowed to offer HTTPS to UK visitors?
That wouldn't affect desktops but with people buying iPads and Chromebooks to replace their computers, it seems we're heading towards trusted computing after all. Then all the nasty crypto can be outlawed. What a grim future.